Basically if you think of a polygon edge as a spline and the surface that connects polygon edges as skin then the technique is simple to understand. I simply arrange the polygon edges of my models so that they flow around the countours of my mesh. Beacuse they are straight edges and not splines they take more experience to visualize but the advantage is the ease and speed at which polygon edges can be manipulated. With splines you have to adjust the location of CV's and adjust their curvature, etc. The spacing of the polygon edges determines the sharpness of the model's angels.
Edges close together produce sharper angles, spaced apart, they produce more gradual curves.
Most of my meshes start life as cylinders. I typically use a 24 sided cylinder. I remove one half of the cylinder so that I can work on one side of the model only. I also cut off the caps on the top and bottom. From a side view, I shape the verts into the profile of the object.