* don’t run two AdWords accounts for the same business
* don’t run two or more businesses in the same account
* don’t run AdSense and AdWords – if your business needs both, have two different people do it and don’t let them have access to each others’ accounts
* be careful using Google Checkout and settle each and every customer issue immediately (good practice anyway)
* don’t run “tests” or check something out “for a friend” or because “it’s a sure fire money making idea”

Too late for you, perhaps? Try MrsC’s “AdWords PI” service to rehabilitate accounts – look in the sidebar under “Consultants and Agencies”.