The key thing is good advice, obviously, which you probley figured by now.
The others are things like; amount of advice, grammer, punctuation, etc.
Us advisors are profanity haters, or as lex_icon would say "the jolly words". So, someone that doesn't swear is good.
If a time comes and you are thinking about becoming one, be sure to send 'thedude' with some pieces of advice that you have given so he can evaluate you.
Who are advisors?
Advisors are the official voice of Funadvice, and are users just like you and me. Users get promoted to advertisers when they've either ranked highly by other users, or have just provided great answers.
How do I become an advisor?
You can become an advisor by first providing highly rated and clear answers. Contact FunAdvice (user thedude or editor) with a few of the answers you've provided and we'll consider upgrading your account to advisor status.
Go to the very bottom of the page, and it will say "Terms of Service", you can read them there. You also agreed to them when you registered, so hopefully you really did read them. :)
I wouldn't send your answers through funmail. Just email thedude or editor and they'll be able to see your answers on your page.
Would I send them through funmail? Where can I get to the terms?