Selling toons doesn't make any real money; it's all about farming resources (ore, glyphs, herbs, gems, fish/meat); there are a lot of addons that help you sell these things, most notably
Auction Profit MasterWhen it comes to selling gold, being in a guild where people buy gold is like, step 1. You will get banned if you sell gold to a vast majority of websites. Tradeing to a known player is the only 'safe' way to go. And by safe, I mean they can still rip you off, but you'll never get banned for it.
Step 2: never trade gold on a toon that farms the gold. Most of the time when banning accounts for selling gold blizzard will only ban the account that is doing the actual trade.
Step 3: Don't worry about getting banned for botting. It's a 72 hour ban now, not permanent. If you get banned, for the next couple weeks after being unbanned, don't bot and play manually. Not admit to botting, or doing anything against the ToS that can be linked to a specific account. Ie, screenshots with botting addons in them.
Step 4:
Step 5: Profit.
Oh, and you'll want to bot on a full server. The more people there are, the more people there are to sell to; I've found that the number of botters/farmers doesn't go up proportionately. You can find which servers are full on this list:
http://www.wowrealmstatus.net/ Note: you cannot transfer characters to full realms, afaik, so, you'll probably want to Recruit a friend and instance run from 10-60 and then bot from 60-80. Bots are really good at killing shit. Secondary warning: full servers can get queues up to like 4-5 hours to login. You will not want your bot to log off for more than 15 minutes during peak hours, unless you don't want to make anything that night, anyway.