Try to go for niches which you know are popular and getting a lot of searches. Then, using keyword tools, find long tail keywords so that you will still be in the same niche, but will have far less competition. That way, you will realistically be able to rank in the top 10 of Google for those search terms.

You don't necessarily have to build a site to take advantage of high traffic low competition keywords. You can also use free web 2.0 properties like Squidoo or write and submit articles to major article directories and get them to the top of Google with some link building.

If you have the knowledge to do PPC, that will work very well too.

Curtis