Understand the Economics Before You Start
This may sound like economics 101, but if you are planning to spend $5000 on a Pay Per Click campaign, then make sure you are generating enough revenues to justify both the financial outlay and the labor costs associated with the campaign. The good news is that you can keep your costs in line by adhering to a strict budget. If you limit your campaign to $100 a day, let's say, and your ads will stop being delivered as soon as you hit your daily maximum, and resume the next day. However, if you're spending $20 to sell a $15 shirt, it doesn't matter how many times a day it happens; you're losing money.