If you have never used subdivision surfaces before, the following workflow description will help you get started:
This model will determine the base topology and control points of the subdivision surface when you convert it to a subdivision surface. Subdivision surfaces are very effective at creasing and refining edges so you don't need to put a lot of effort into capturing those types of features in the polygon mesh.
You can also convert to subdivision surface to check the conversion and then undo back to the polygon model.