Take your time understanding how Adwords works, else you'll find yourself wasting $$$$ on advertising there. Probably the most important thing to learn is creating ads that will result in high click-through rates (CTR). Without high CTR, you'll end up paying higher for keywords clicks than the competition. Also, focus on landing pages -- make them compelling, with a unique sales proposition (what differentiates you from the other advertisers). Adwords itself if easy to use -- it's getting conversions that's the tough part...