Keyword Analysis

Keyword analysis plays the most important part before starting a site. It helps you to determine the the effort you have to put to make it top at SERP and many others.
It also helps you to calculate the average EPC which you should get if your site monetize with ads and deep analysis helps you to determine the keywords you have to choose to target.
Theres a lot of tools available to Analysis Keywords but I recommend Google Keywords Tool. It suggests you the smiler keywords which you might want to target, average CPC, average monthly search volume and many others.
Just give it a try.