Here is a good article I just read on msn.com. Most of this stuff is common sense to most of us around here, but its a good list nonetheless:
http://articles.moneycentral.msn.com/SavingandDebt/SaveonaCar/20waysYouWasteMoneyOnYourCar.aspx
http://articles.moneycentral.msn.com/SavingandDebt/SaveonaCar/20waysYouWasteMoneyOnYourCar.aspx