For example, when you search for "computer", Best Buy has an ad at the top of the search results, in a bluish box thing. The rest of the ads are on the side. How do you get in the blue box?
The blue box is a combination of CTR and QS for the most part. Your CPC will also factor into this, but will probably play more of a role in the CTR portion of the equation.
Check the common AdWords questions answered thread at the top of this forum...this is one of the questions