I don't think Adwords is a good place to start. You can waste a lot of money if you don't know what you are doing.
1st place to start is to figure out the right niche. Something you know about thats not too competitive. Start with this article then read some of the other ones in the niche marketing section.
Think Small to Earn BIG! Niche Marketing Insights
2nd step after you decide on a niche is keyword research. Whether you do Adwords or a regular site you need to know the best keywords to target. Lots of tools for keyword research in the niche section and the tools section.