How to study with the candidate genes? - (Jan/30/2011 )

I am about to start a project looking at the methylation status of some candidate genes. I need some very basic information about candidate gene studies itself, how it workes and what is it basically? Some general information regarding how to study candidate genes?
What is the best way to pick them up and how I can be sure that those are good candidates?

Thank you very much

Can I ask candidate for what?

Candidate epigenetically silenced genes due to DNA methylation.