First Karrass  then Cialdini  have provided excellent summaries of negotiation strategies and the use of influence to gain advantage. Both also explain how to defend against influence tactics.
Karrass  explains that change comes from learning and acceptance. Learning comes from hearing and understanding, while acceptance comes from comfort with the message, relevence, and good feelings toward the underlying idea. These are both affected by audience motives and values, the information and language used for presentation, audience attitudes and emotions, and the audience's perception and role in the negotiation. By controlling these factors, advantages can be gained in negotiations. Additional factors include:
(1) Credibility of the presenter helps gain advantage and it attained by suitable introduction and historical behavior;
(2) Message content and appeal are gained by (a) presenting both sides with the favored viewpoint at the start ane end, (b) repetition of the points to be made, (c) stating conclusions, (d) arousing a need and then fulfilling it, (e) avoiding threats, which tend to be rejected (f) asking for more, which tends to get you more, (g) stressing similarities, (h) tying hard issues to easier ones, (i) not creating defensive situations, (j) not belittling other views, (k) being friendly and sympathetic, (l) asking for advice, and (m) appealing to self worth, fairness, and excellence;
(3) Situation setting and rewards also play important factors and can be enhanced by (a) making the audience feel worthwhile, (b) reinforcing pre-existing opinions, (c) presenting a balance of ideas, (d) avoiding or offering to remove ambiguity, (e) using social pressures to your advantage, (f) accounting for audience facts, methods, goals, and values, and (g) understanding and dealing with issues of power and influence.
(4) Media choice for messages can also be important. (a) Letters are good when establishing justification, for getting letters back, for establishing justification, and when interruption is dangerous, (b) face to face is better when personal presence brings regard or respect, when visual indicators will help, or when more or less information may be desirable. (Karrass was writing before FAXes and Email were widely available).
Karrass  provides a three dimensional depiction of goals, needs, and perceptions and asserts that people are predictable. The three dimensions he identified are:
Goals: (1) Money, (2) power and competence, (3) Knowledge, (4) achievement, (5) excitement and curiosity, (6) social, (7) recognition and status, (8) security and risk avoidance, and (9) congruence.
Needs: Maslow's Needs Hierarchy includes (1) basic survival, (2) safety, (3) love, (4) self worth, and (5) self-actualization.
Perception: Perception of goals include: (1) How do you want opponents to see you, (2) how do opponents see their goals, (3) how do you see opponent goals, (4) how do you want opponents to see your goals, (5) how do you think opponents see your goals, and (6) how do you see your goals.
The object of a successful negotiation is to optimize how everyone sees their goals.
Karrass  also lists a series of specific negotiation techniques and countermeasures, and his work has been widely hailed as seminal in the field. Millions of people have now been exposed to his work. Some of the specific tactics he describes include:
|Timing||Patience||Willing to bear with the situation for as long as it takes.||Lowers expectations of rapid progress, may cause a desire to yield more rapidly to make progress.||More patience, loss of value with time, increased social pressures.|
|Timing||Deadline||Time limits on completion of the negotiation may drive to concessions. Many times the one with more time goes by the other parties' deadline, thus making it harder to 'win'.||Whoever has longest can take advantage.||Don't reveal deadlines, or set other parameters to limit negotiation points.|
|Timing||Speed||Quick agreements can be made on small points, one after another, until there are no points left to be agreed upon.||Causes a pattern of saying yes which carries through to future issues that may not have yielded a yes and creates an expectation of rate of progress.||Quick counteroffers, refusal to make partial agreements, or a slowing of the process.|
|Timing||Fait accompli||Actions that alter the balance of bargaining power by virtue of already being in place, thus making them far harder to undo.||Reduces expectations, increases work to change things.||Tit-for-tat reprisals, demonstration of willingness to undo what seems nearly impossible to undo.|
|Timing||Surprise||New conditions or requireements are added after part of the negotiation is completed.||Lowers expectations and changes the value of previous sub-agreements.||Changes require restart of the whole negotiation process, make similar changes to previous positions, make unrelated changes that gain back whatever is lost.|
|Timing||Status quo||Go with the same agreement we had before unless and until the new agreement is completed.||Lower expectations for new agreement, bypass deadlines.||Go on strike, indicate that the deadline ends the old agreement, go with the old agreement with an 'adjustment' for changes in condition (cost of living increase is an example).|
|Timing||Stretchout||Deliberate extension of negotiation over a long time.||Force the opponent to expend resources, create internal friction, increase pressure for agreement.||Walk away, start taking desirable issues off the bargaining table, start increasing the price, other time dependent reduction in opponent expectations.|
|Inspection||Open inspection||Unlimited inspection is permitted.||Openness, honesty, nothing to hide.||Do inspections and verify it.|
|Inspection||Limited inspection||Access for inspection is limited at the control of the party being inspected.||We are open, but we won't let you look around forver before making progress.||If limited inspetions are inadequate, so indicate.|
|Inspection||Confession||Full disclosure of all known items of interest are made.||Openness and honesty is laudible.||None needed except verification.|
|Inspection||Qualified confession||Questions are answered but faults are not offered.||Appearance of openness but information is only selectively revealed as needed.||Ask a lot of quesitons, including general ones like 'Are there any other things that might be relevant..."|
|Inspection||Third party||Access by agreed upon neutral third parties.||We are open and honest, but we have legitimate reasons for limiting your access.||Question sincerity, find a good inspector.|
|Inspection||No admitance||No inspection os permitted.||Reduction of expectations / can be used to cause mystique.||Go elsewhere, require alternatives to inspections.|
|Authority||Limited authority||The person at the table is not authorized to make the final deal.||It allows negotiation toward the best we can get from you, followed by having to get more from you.||If authority is know ahead of time, provide a non-authoritative negotiator on your side. If this is revealed after negotiations are underway, treat as a possible deception.|
|Authority||Approval||The person at the table can negotiate, but the deal requires approval.||Lowers expectations of finality, creates potential for refusal to approve, allows negotiator to 'blame' on someone else, allows negotiator to act like they are on your side.||Seek approval at every step, negotiate in good faith to a final agreement and refuse to take less, indicate that you too need approval and get their approval first.|
|Authority||Escalation approval||Deliberate creation of additional approvals.||Lowers expectations, an escalation of the items in "Approval".||As in "Approval".|
|Authority||Missing man||Deliberate absence of person with final authority.||As in "Approval"||As in "Approval" or indicate that you will be willing to reschedule for when the final authority is available.|
|Authority||Arbitration||Third party decision - neutral or biased.||Create at least the illusion of impartiality and fairness, lays blame on others.||Refuse to permit it, accept a well known mechanism, accept only really trusted third parties, back out.|
|Association||Alliances||Strong partners||Strengthen bargaining power, strong desire for mutual benevolence.||Foster this.|
|Association||Associates||Friends||Slight strengthening of bargaining power. desire for mutual benevolence.||Foster and improve this, ask for references.|
|Association||Disassociates||Mutual non-friends||The enemy of my enemy is my friend.||Use caution - it is not always true.|
|Association||United Nations||Broad-based alliance of industry members.||Strength in numbers.||Try to use it to improve ties, gain reference information.|
|Association||Bribery||Payoff and collusion||Someone pays someone for an advantage.||Report to law enforcement, report to management, refuse to deal with them, take their money (legally only - give them a receipt and fair market value) and don't weaken your position.|
|Amount||Fair and reasonable||Everyone wants to believe they are fair and reasonable.||Appeal to morality and sense of fairness.||Get select examples of competitors and raise price to meet theirs, provide explanations for why yours is fair and reasonable at a higher price.|
|Amount||Bulwarism||Take it or leave it.||Expectations are forced toward win or lose - no shades of gray.||Leave it.|
|Amount||Nibbling||Take small concessions one after another - after other issues are settled.||Many seemingly small items come out to a large difference.||Nibble back. For every nibble, extract a price.|
|Amount||Budget bogey||My budget is only so much.||Puts artificial limits on price.||Offer lower-quality alternatives that meet the budget, help them increase the budget, spread over multiple budget items or cycles.|
|Amount||Blackmail||Since you have no choice, they can ask whatever they want - up to a limit.||Investment in this line leaves you with little choice.||Change directions, nibble for other concessions, change other terms, walk away.|
|Amount||Escalation||After agreement, take your part and raise demands.||Lowers expectations and feelings of self-worth||Return fire - don't let them get away with it - Offer accepted is a legal contract - etc.|
|Amount||Intersection||Tie together otherwise seperate negotiations.||Creates complexity and opportunity for tying easy things to hard ones.||Refuse to tie, tie still other items, deal with the increased complexity, etc.|
|Amount||Non-negotiable||Select items can not be altered.||Lowers expectations with respect to those items and creates automatic wins for one side.||Don't buy into it, create your own non-negotiables, negotiate harder for other items, walk away.|
|Amount||Chinese auction||Multiple opponents are played off against each other.||Creates competition between competitors.||Ignore the others and negotiate for yourself, walk away, explain that after they have their best offer elsewhere, if they want to deal with you, you will be available to discuss it, trade price for other terms.|
|Brotherhood||Equal brothers||Based on equal status.||Expectation of tit for tat.||Fulfill expectation with appropriate caution.|
|Brotherhood||Big Brother||Benevolence based on higher status.||Since I am so much bigger I will help you.||Thanks, I could use the help.|
|Brotherhood||Little brother||Charity desired based on lower status.||I am small and you are big, please be nice.||Recognize that they are potentially exploiting your desire to be good.|
|Brotherhood||Long-lost brothers||Search for relationship and status.||Trying to find common ground.||Provide it.|
|Brotherhood||Brinkmanship||Intersecting destiny based on high joint risk.||Threat-based and potentially very dangerous.||Decide oif it is worth it and if so expect serious consequences and prepare for them.|
|Detour||Decoy||Attract or snare||Seemingly excellent offer is used to get you to invest time and effort which you are then motivated to get value for.||Recognize and walk away, negotiate harder to get back full value, set parameters and expectations appropriately so that you are not snared.|
|Detour||Denial||Negation or retraction of statement.||Create false impressions, generate concessions to indicate real parameters, lower expectations, increase anger and frustration, create delays.||On the first time, indicate displeasure, and take back all of the previous discussions, create pressure on their side to stop it.|
|Detour||Withdrawl||Walk away from negotiations.||Lowers expectations, may generate wild concessions just to get you back to the table.||Don't give in, create social pressures to bring them back, seek out alternative deals.|
|Detour||Good and bad guys||Good cop bad cop.||You confide in the friendly one, who looks good in comparrison to the unfriendly one.||Recognize the tactic and don't be offended or fooled by it.|
|Detour||False statistics an errors||Creating deceptive statistics||The statistics have the appearance of authority.||Question, understand, and verify this sort of information.|
|Detour||Scambled eggs||Creating dilliberate confusion on issues or figures||Confusion is used to cause the negotiator to make mistakes and get in over their head.||Know when you don't know enough and ask for help, bring in experts, explain that it is getting too complex and that if it isn't simplified, you will have to seek alternatives.|
|Detour||Low balling||Initial low price with high add-ons (close to bait and switch)||Create expectation of low price and momentum to buy, followed by seemingly small adjustments that add up.||Try to get the add-ons for free, nibble at the add-ons, get the 'whole' price and then compare it to alternatives.|
|Detour||Scoundrel||Larceny by never-ending negotiations||Wastes time and effort while consuming your resources.||Detect and walk away.|
Karrass also provides a list of negotiating techniques including: (1) agendas, (2) questions, (3) statements, (4) concessions, (5) commitments, (6) moves, (7) threats, (8) promises, (9) recess, (10) delays, (11) deadlock, (12) focal points, (13) standards, (14) secrecy measures, (15) nonverbal communicaitons, (16) media choices, (17) listening, (18) caucus, (19) formal and informal memorandum, (20) informal discussions, (21) trial ballons and leaks, (22) hostility releivers, (23) temporary intermediaries, (24) location of negotiation, and (25) technique of time.