Independents can be tough when you don't have references.  I'm just starting and I get a fair number of no-callbacks.  Here are some things that work for me:

- Use email for the first contact, then follow up with a phone call.  Provide lots of info in your email: full name, work phone, etc.
- Try an agency.  There's usually someone to answer the phone and they're less choosy than independents.
- Check your regional board for travelling indies.  I don't know why but I've had better luck with them.

There's lots of good information on this subject in the Newbie board.

Good luck,

Dan

As far as reliability goes, use the reviews as your guide.  There are bait and switch, overbooking agencies as well as highly professional agencies.  Similar with independent ladies.  

If you don't have references, my understanding is that agencies can be easier to get an appointment with.  Be prepared for employment or other verification.  

A search on the various boards for Independent Agency (with "include text" checked) will yield many discussions.  Below I've linked to a discussion last week on a regional board.

Go have some fun!