Set a daily budget
This may seem like a no brainer but for some reason a lot of people do not set a daily budget on their PPC campaigns. You need to come up with a number you don’t want to spend. I have seen companies not pay attention to their spending and get huge credit card bills. This may not be too big of a problem if you credit card has a low limit but if you are using a gold or higher Amex card you can get a monster bill at the end of the month. This could ruin some people. With Google Adwords you need to set your daily budget lower than you want to spend because they will overcharge you every time.
