Take pictures of your toddler. Make sure that he is smiling, enthusiastic and looking straight into the camera.
Engage your toddler socially to help her develop social skills. Personality is important to modeling agencies, not just looks.
Get your child used to having to sit in one place for hours at a time, similar to what he would have to do for a modeling photo shoot.
Pay attention to what is said of successful child models by those casting them, in order to get a better idea of what it'll take for your toddler to be a successful model.
Don't limit your toddler's opportunities to modeling agencies. While they are a good way to get your toddler started in the modeling world, it is a good idea to pay attention to casting calls in your area, as well. These can be found in the classifieds sections of websites and newspapers.