Well you can either do a Polygons --> Smooth which will increase the geometry. You can do thins to either the whole object or just certain faces depending on what you want (this will also help keep certain areas sharp) or you could do Edit Polygons ---> Normals ---> Soften / Harden which will change the look of the edges. So it will keep the geometry in shape but just give the edges a sharp or soft look.

Hope this helps.