Does the site offer advice?
Dating advice, relationship advice or other tips that can help you along are good indicators of a site that really wants you to succeed. You are really looking for a partnership with the site as much as with a relationship partner. In many ways, it is a lot like interviewing for a job. If somebody offers advice you at least listen. You may not use the job or dating advice but every little tip could help.
What do you really want?
This could be quite a bit trickier to answer then you may think. Having an idea of what you want and what will work can be a lot different then what will actually make the best match. If a site offers a personality or matching test, be honest with whom you feel you really are. There is really no sense in lying to yourself and wasting everybody’s time in the process.