I work for SpyFu. We can get you interesting keywords since we know what everybody's buying. I'm not too familiar with other tools TBH, but am pretty sure Words

I work for SpyFu. We can get you interesting keywords since we know what everybody's buying. I'm not too familiar with other tools TBH, but am pretty sure Wordstream take more of a similar words approach. So both can yield good ideas. Also Google's keyword generator is very good although they have somewhat of a conflict of interest, at least in the short term to get you to buy words that are profitable for them rather than you. I also recommend not broad matching, and just using the words you specifically pick. Stay away from short terms, i.e. "backup" and go for one's like "complete backup". Also, don't use the content network for things you want people to take action on. If people are taking action, they're much more likely searching than browsing a page and clicking adsense. There are exceptions like video games and appeals to do other leisurely things in which the content network is actually better. Think about your users and where you're likely to find them. :)