Recently a friend of mine was banned from Wikipedia. When I found out, I was a bit surprised... until I looked at his account. Most of his edits were on controversial topics/people, added no value to the entry, and even - in a few select cases - removed accurate criticism from his friends pages. Regardless of whether or not you agree with his point of view, this is not the way anyone should go about editing Wikipedia... so for record, here's how to do it legitimately:

• First, if you're going to contribute, contribute. If you're just going to edit, go away. There is a fundamental difference between editing and contributing. Contributing implies giving something of value... editing is just changing content.
• Next, if you're going to contribute on a contentious topic, it's good to build up a non-contentious history first. And yes, almost anything political can be considered contentious. If you contribute information to various topics like your favorite teams, your alma mater, your hometown, etc, you can build your history relatively low-key. If your account looks like it's just a political attack tool, it will be blocked... and rightfully so.
• Next, only post verifiable facts and then post all the facts. Posting a link by itself just tends to annoy people. If someone or an organization has come under investigation, it's fair to note it...and provide the supporting link. If they've since been cleared, you can still note the investigation, but the results should be noted too.
• Next, don't bother trying to hide who you are... they'll know. Since every edit is tied to an IP address, if you're editting from Google HQ or a US Senate office, they'll know pretty quickly. In addition, they can track down everyone who has ever contributed from a range of IP's. There have been numerous dust-ups where a House or Senate staffer have edited their boss's pages. Bad Idea. And if you have multiple "identities", it's trivially easy to identify them as a group. Just don't do it.
• Next, don't ever edit your own page. You're probably a bit biased about yourself... does this need any further explanation?
• Finally, don't get into revert wars. If someone else undoes something that you've done, check out their profile. If they're a total newb or editting from a biased location (think: Microsoft employees editing the Apple entry), feel free to revert back and give a statement to defend it. If they're an established member, go to the page's talk page and defend your edits. If you can make a case on a) why it is relevant and b) why it's not just an attack or whitewash, it's likely to stay... and the community will end up defending it.

The goal of all of this is to demonstrate that a) you can follow Wikipedia's contribution policies, b) you actually have something to contribute, and c) you're not just a troll. These rules apply to everyone regardless of who you are... even Jimmy Whales can't edit his own page.