Take a personal development course ASAP. Get a copy of the book Even Eagles Need A Push copyright 1990 by David Mc Nally, a Dell Trade publication. It is based upon the idea that even the majestic eagle needs to be pushed out of its nest before it can begin to fly (succeed). The book is a self study course in itself. If you'd prefer a seminar setting, one is available through Management Dimensions, Mpls, Mn., 612-339-5335.

You need a basic track to run on in the influence management world. Try on W. Edwards Deming's philosophy by reading his book Out of the Crisis , copyright 1982, 1986 , MIT press. People need to be able to understand where you are "coming from". If his ideas fit you, this book will become an important resource to you.

This is a method for breaking down human interactions into their simplest parts. A good understanding of these principles will help you to understand why certain kinds of responses occur and how to stop (or start) arguments. A structural diagram of the personality is developed. It is presumed that a person always acts or reacts from one of these three states: the Parent state, the Child state or the Adult state. The reasons for these beliefs are developed using simple diagrams. These concepts will stay with you and remain useful to you for the rest of your life.
Three good books on the subject:
I'm OK, You're OK, Thomas A. Harris, Copyright 1967, Harper & Row
Born to Win , James & Jongeward, Copyright 1971, Addison-Wesley Publishing Company
Games People Play, Dr. Eric Berne, MD, Copyright 1964, Random House

You need to become known as a problem solver. As you are seen diagnosing and solving problems that bug other people, they become more comfortable with you.
There are many good texts on problem solving, but here are a couple that are very key to me:
-The Art of Getting Your Own Sweet Way, by Phil (Quality is Free)Crosby. This is a 1970's book, but just as current today as the day it was published. It is a very personal book on how to handle tough personal decision making (which, after all is the level it all boils down to sooner or later anyway).
-The Rational Manager, by Kepner and Tregoe. This is another 1970's book which explores basic problem solving techniques. It is THE basis for the development and honing of problem solving skills. These guys wrote a follow up Book 10 or 20 years later. I think it is titled "The New Rational Manager", but it doesn't cover the basics. I'd put off reading this newer release but you must definitely read the first one ASAP.

This is a 20 or 30 year old concept (at least), but one that the influence manager really needs to have ingrained in his or her being. Think of any situation as having 2 "sides"; "WE" on one side of the issue and "THEY" on the other side. There are only 4 possible outcomes from any interaction:
1. WE lose and THEY lose.
2. WE win and THEY lose.
3. WE lose and THEY win.
4. WE win and THEY win.
Which of these 4 situations sounds like the more permanent solution?
Obviously, in the first three outcomes, SOMEONE is LOOSING. Only in the fourth outcome is everyone satified (WINNING)and therefore more likely to accept and live with that outcome!! We often hear sports analogies applied to real life, but I submit that this is often counterproductive. In many real cases, there DOES NOT have to be a LOSER at all.
I suggest that you NEVER even think of putting forth a solution that is less than WIN-WIN. This WIN-WIN approach WILL ALWAYS be noticed by the people for whom you labor. They may doubt the quality of a solution you put forth from time to time, but they will never doubt your sincerity.

As you know, many people talk as though they are on one side of an issue, but later on you find out that they didn't mean what they said. To be a successful Influence Manager, you need to be able to figure out what people are really after.

Read the book Winning Through Intimidation, copyright 1974 by Robert J. Ringer (a Fawcett book). I know the title sounds AWFUL, but I think this book teaches one how to identify the hidden agenda and how to profit from the knowledge. It uses real live examples from author's experiences in the real estate world.

Put yourself in a position to constantly help other people to get their work done, and done more productively. I always felt that returning phone calls promptly was a way to enable the other person to get their job done quicker, based on the thinking that 30 seconds to answer the question they had might save them hours in completing their task, regardless of where they are in the management chain.

Get the Meiers-Briggs profiles for all the important people who have a stake in what you do.. Use any opportunity to discover more about those you need to influence. Think back to any time when you were embarrassed by not being able to sell something in a presentation setting. Can you trace your failure back to a lack of insight into the mind of one or two of the principle stakeholders in the decision process? I sure can!!! There is always at least one person who can tell you, after the fact, the little details that could have made the difference. "Digging out" later is always harder than "Digging up" before hand.

I know this is a tough comment to make in these days of too much to do and so little time. But whenever you need to get involved in a new subject, take some time to learn more than just the minimum requirements. Practice a little "what if" on yourself to suggest the depth that you need to go to if various scenarios where you were on the "hot seat" did occur. I have heard that lawyers never ask a question unless they already know what the answer is; in other words, they never want to be tripped up in front of an audience. Even if the situation is relatively unimportant, it detracts from the trust that you have worked so hard to build. For sure, know enough that you NEVER make something up! If you DON'T know simply say so and tell the questioner that you will get back to them later. Then make it a very high priority to get them a COMPLETE answer, even copying everyone else who was in the room at the time, if necessary.

See how people who do what you do deal with influence management issues. Get involved with your company's Quality Manager to see, first hand, how they produce successes and where THEY have trouble with Influence Management. Go to association chapter meetings. As usual, the networking done during "elbow bending time" is often the most beneficial.

Go out of your way from time to time to show people that you really care. Then when you need to sell something, you don't need to remind people that they "owe" you; rather they will want to work with you.

Understanding and using Negative Objection Analysis is vital in influencing other people to do things. The course "Oral Presentations to Management" presented by Dr. Roger Mosvik of McAlester details this process.
It is the process for always knowing what the stakeholders in any situation NEED and WANT in order to behave as you want them to. Essentially, you need to write down at least 20 Objections that your audience could make to the proposal you are trying to sell them. Then you rank these objections and solve the most important ones, building those solutions into the front end of your presentation. This often means developing a "dossier" on the "stakeholders, so you KNOW how they think.
The kind of influence you will be making will often occur in a presentation setting. The workbook handed out with the above mentioned course contains a 2 page MAGIC FORMULA for developing and delivering presentations. This is the most powerful tool I have EVER found. If you use this tool as it is laid out here, you WILL prevail!!!

That's it in a nutshell. Start now and keep at it for the rest of your life.
The final note: You have to BELIEVE in what you are doing. My own test for the quality of what I have done is to look back later to see if I have been believing in the right things. If so, then I feel that I have the right and the mandate to continue along the same path... making minor or major adjustments, so that I can continue to feel excited about what I am doing.