Most of this is common sense but important nonetheless. This is a guide to keep your main account safe as related to scamming accounts and gold.
1 - NEVER scam using your main account! (obvious of course)
2 - NEVER link your phisher website using your main account! (do so with stolen account that are about to run out of gametime or are worthless)
3 - When you are selling the scammed goods don't list it all at once or use two characters or more to list it. If the person(s) you scammed happen to notice that all their stuff is being sold by one guy, you're screwed.
4 - Use a seperate email address for your scammed account than you have listed as your main's email account. Same goes for the phone number if you change that.
5 - If you are going to sell your gold then use a SECURE stolen account (secure meaning one that won't be recovered) if you have one. If you don't have a secure scammed account then just be very very (I can't stress it enough!) careful not to say anything about selling the gold to the buyer. On a side note, only sell to legitimate websites, not individual players as they are more likely to scam you.
To summarize, always follow the user agreement on your main. Avoid linking your scammed accounts to your main account. Your IP address is very hard to cover unless you use a proxy (I don't know much on the subject, just search around mmowned) but I've heard from multiple sources that Blizzard only really does IP banns when an account is logged on from on part of the world and then the opposite in an unreasonable time period (like from US to China in 2 mins, chances are you're getting powerleveled.)