I have a new idea for a site. The problem is that the niche is already full of other competitive sites. So, what I really need, is a way to find what keywords are most used for the searches and what competition is for them. I tried the google adwords keyword tool and it looks pretty interesting, but I do not understand, if the search volume is HIGH, and the competition is also HIGH, should I still use those keywords or search for others that have less competition? Is it preferable to have 0.0001% of the high searched keywords or 1% of the low searched keywords? To give an example, let's talk about the "Health" keyword... how do I find good keywords for this domain?
I recommend wordtracker.com. They have a free (by email) version as well but you can pay the weekly amount as it is more than enough as a starter, to do a thorough analysis and then go from there. I would also recommend reading their documentation and FAQs thoroughly and see what the tool is capable of doing before you actually subscribe to it and end up wasting time during your subscription, as there are a few things you can accomplish with the tool. wordtracker.com/index.php?pg=documentation. On the right hand side they also have a link to their knowledge base.