This is something that you will be doing time and time again, and submitting it something that all models must do. Well those who are not discovered on the beach in Brazil.
When you submit keep it short and all about your look.
An agency wants to know (1)How you photograph and (2) your stats (3) different looks-with a smile and maybe if you have long hair, pull your hair back so that the agent can see your face in the photos. Straight on shots work best. -don't hide your eyes.
Speak about yourself in a note: Your hobby's any modeling experience you have and you could even include in the mailing a recent tear sheet or catalog job you did. If you don't have any experience submit some photos, could be 5x7 prints, or a compcard you can make yourself from www.compcard.com.
Submit your phone number,- even though email is popular most agents will contact you by phone number.
Also an agent doesn't want to hear about the other three agents you work with, so have them call you to get intouch with you, not your other three agents for more information.
Becareful about the images you submit. Personality is big, so don't send shots that are too fashion-like- especially if you are short, and don't send images that are overly sexy. Even if you have a great booty. (no one wants to open mail and see your booty blunt and in their face.)
Simple shots of yourself are ok too, looking straight into the camera and a profile shot and an energy shot of you smiling or laughing naturally is nice.
Some agencies have open calls,- where you go and show the agents your portfolio and photos, other times it is best to just submit by mail. Not email( unless the website requests that) but to them directly at the agency.
Usually if they do not want to work with you then you will not be told that, if you don't get a call in three weeks, then figure they were not interested. It could have been your photos. It could have been they just don't have an interest now but they could later. But this doesn't mean give up. It means keep mailing other agencies and once you have updated your photos you can always submit again with new ones.