The most important thing to determine in the beginning is what type of model you hope to be. Clients look for different things in their commercial models to their catwalk models, and consequently, the images that you include in your modelling portfolio should reflect the type of modelling you want to get into. A lot of time and cost can be saved by specifying this early.
While pursuing your passion to become a successful model, you also need to be realistic and aware of the stereotypes that are a part of the modeling industry. In most cases, your body type would define the kind of assignments you get, as most clients have a pre-conceived notion of what they feel fits their brief. For example, its harder for shorter or petite models to break into fashion modeling. While these stereotypes are constantly being broken and you certainly can break them on your way, it helps to be realistic and honest about your strong points. This would increase your chances of achieving success and reduce setbacks and rejections.
Making an informed decision about the type of modeling you want to pursue would bring clarity and focus on how you want to shape your modeling portfolio. For example, as a freelance model you would need a lot of variations in your shots, but as a high fashion model, you would need to focus on high fashion images.