To make your adwords campaign more effective, there are two tips that may help you.

Capitalize on low price keywords
If you target thousands of low price keywords instead of only a few high price keywords – you can usually get the same/more traffic at a lower cost. Let me give you an example:

You manage a website that sells new cars. You begin your adwords PPC campaign searching for keywords to bid on. The common keyword “new car” may be searched for, say, 1000 times a day. Which seems like a good keyword to generate traffic to your site. However, “new car” has a PPC bid price of $4.50 a click. Lets say 100 people click on your ad which costs you $45/day. For 100 visitors. Now lets consider another option…