First, this isn't about the physical characteristics of a model's body, that is a very subjective thing and certainly what I like in a model will differ from what some others like. In addition, I don't always gravitate toward one body type, height, color, weight, eye color, or anything else. I find someone that fits the vision in my mind. Again, all subjective.
1) You are a business. Not just a model. And in realizing you are a business you do the things of other successful businesses. You have a service you perform (technical skill; modeling) and you know how to (employ administrative skills) market, communicate and respond to your customer base to expand and grow your business and you do these actions.
Factually every artist is a business. And the successful artist will not only know their technical skill cold, but know also administrative skills and will use them to their advantage over other artists who only focus on their craft.
There are GREAT photographers and models out there that no one has heard of and it isn't because their work isn't great, it's because they aren't treating themselves like a business. There are plenty of mediocre photographers as well who are in business and they do alright, not because of their skill but because they can run a business.
2) Your skill set is the technical aspect of your business but it's nothing if you neglect the administrative side of your business which includes:
The purpose of this writing was to give you the correct perspective as to how to treat yourself as a model and that is as a business. There are many books on what makes a successful business. A modeling agency is such a place that handles the administrative functions of your business for you so that you can focus on your craft. They will take their cut as well. The advantage of being part of a reputable agency is that they will be able to market you and get you work. But understanding you are a business may give you an advantage from the start!
Feel free to chime in on what you think as well. We all have a different point of view.