Scratch that. In fact, never ignore the T&Cs of card companies. Actually, never ignore the T&Cs of anything that involves money because more often than not, the devil is in the detail. Most often, we only end up signing for additionals we didn't know and definitely didn't need. So make sure you read all the documents thoroughly, even twice for that matter, just so it doesn't backfire at a later stage.
6. Exceed your credit limit
It's self-explanatory really. Like mentioned before, a big amount means a bigger interest rate. So never bite off more than you can chew.