Project Management Politics
An article in the June 2006 issue of PM Network discusses the political waters that a project manager must navigate regardless of company, project, or location. A sidebar in the article makes for a good summary.
After informal and verbal communications, send a friendly note summarizing what was discussed and agreed on. Seek confirmation that you understood things correctly. It's not only polite, but it can clear up confusion long before problems arise.
And don't gossip. If complaints come your way, ask for clarification. Seek to understand the complaint especially if it is about another person. The key is to listen. In this way you give people an opportunity to vent without actually jumping on their bandwagon.
Learn to talk less. Instead, listen first and then think twice before offering advice. This sort of behavior can result in a gaining a reputation of "being a wise old sage instead of an underhanded dealer."
Forewarned is Forearmed
Don't fall in to the trap of asking for or giving favors when dealing with known hard-ball politicians in your organization. Most people do favors for each other as a matter of course. Politicians, on the other hand, don't think this way. They evaluate each request and then decide whether to cooperate or not depending on how it serves their purposes. This might seem predatory and you'd be right. Although you shouldn't work this way, it is important to understand that others do.
Learn About Cultures
Exposure to projects that cross country borders is a great way to learn to suppress pride and arrogance. Attending professional training events in areas that are outside your normal area of comfort is another way to accomplish the same thing. Both of these techniques can translate in to more effective interpersonal relations.