Welcome to my guide on making a good pseudonym. I will list things to do/not do

1. Numbers are BAD! BAD! BAD! Numbers will turn away the more serious people at a fair rate (admit it, who would befriend, much less pay attention to, John1825712085?)
2. Using a product in your name is also bad. Do not name youself "WoWGoldVendor". This is more of a username than a pseudonym thing, I guess, but it's bad.
3. Use a random name generator. This is good. It gives ideas. I use two pseudonyms, Erathoniel, and Winsu Drako. Erathoniel is from Eowond (Tolkeinian Elvish), Winsu Drako came from Mace Windu (and too much caffeine).  You don't need to use a random name generator, as Winsu Drako proves (how many Winsu Drakos do you know?), but you will wanna. Neo Anderson, James Smith, and whatnot should be avoided. However, Jameson Anders would not be too bad for a pseudonym. You'd have people who wouldn't figure it out, and it'd be ok on the eyes.
4. Do not include words. Kettle Pot is a terrible name. It's like something out of a comic book.
5. Do not steal characters. Nobody wants to play with even Iron Man, much less Iron_Man, IronMan, or IronMan/Iron_Man/Iron Man 97&2/5, and you'd be hard pressed to get conversation with any of those names. Unless, of course, you're a metalworker.
6. Pseudonyms should not include harsh language, slang, or double intendre. Even accidentally, these will probably get you at least shunned, at worst banned.
7. Do not name yourself after geographical features, web browsers, famous people, or, heaven forbid, common mythological characters. (Though that's technically under the Thou Shalt Not Steal Characters, just more legal)
8. Pick a name that works in a setting. Erathoniel is rarely seen in Sci-Fi, though Winsu Drako is not too commonly seen in a modern setting (I figure Winsu sounds techie, and Drako sounds fantasy-like), though not having a modern setting name, I use Erathoniel to identify myself.
9. No attacking other people in a pseudonym/username. StupidBush/BushSucks, DarnLiberals, or YourMommaA(Term-for-Prostitute) all are terrible for this reason.
10.  Use one username/pseudonym everywhere you can. It makes it easier for people to find you. For instance, Anticheese from the GHWiki showed me this site (though I did use his real name too).