Keep your photos clean, and attractive, fresh and I think the faces on a hair color box are good to use as an example.
When you are mailing an agency petite models should be mailing a commercial print agency, alot of girls over-do-it with makeup in their photo submissions which is why the agencies say to NOT wear makeup in the photos you send and to NOT style your hair....You want to show yourself natural but you also want to look pretty... I an example of makeup would be the face of a girl on a hair color box, or in a jewelry ad. Or a wedding magazine, those are ideas for the type of makeup you could have... not too bold in the lipstick, but curling eyelashing is totally ok, ( most girls do that anyways, don't worry about that part). You want to look like you, the reason the agencies say " don't wear a lot of makeup is because they don't want you to cake it on like you are going to a rock conert and they can't even see your face. A little eyeshadow is ok, like a light color, gold, or light pink, or nothing. Tweeze your eye brows but not too thin. You can blowdry your hair but try to keep it OUT of your face for the headshot photo. I would focus more on your expression, looking poise and pretty -the best idea I can give you is to compare it to the girls on a hair color box , nice smile, fresh look,- as a commercial print model, and as a petite model, you want to show your face forward, straight to the camera, or tilted a little but again I would refer to a hair color box for posing. And you can brush and blow dry your hair, just don't pile it like a bee hive or like a diva!
The best thing is to remember to be You. For print modeling you don't have to be Drop dead gorgeous but you do need to have a nice fresh shot of your face. You should make a comp card (www.compcard.com) and even if you only have two photos it is ok, it is good to have a comp card as a marketing tool. If you can’t afford one right now then you can use a local printer or even a home printer with photo paper and print an image that makes you look happy, friendly, with great skin and smile with your eyes. Usually an agent will call you back.