Here are a few things to consider before mailing a modeling agency.
1. Visit their website and see the type of models they work with and the clients they have worked with.
2. It would be best to send a tear sheet you have gained and a few photos in the mail.
3. Before going to an open call, ask questions. There are a lot of GREAT modeling and talent agencies out there but also there are a lot of scams, so ask questions about the agency before you go. Or research them online by Googling their name.
4. When you represent yourself a full front face shot is best and a body shot and an action shot.
5. Include a small note about your experience, or include a resume.
6. Target modeling agencies which work with models of all heights, not just fashion.