There are a few ways to model a basic torso. One such way is using the loft command with 4 or more splines. This tutorial will provide a quick look at a way to make a basic torso using loft, and how to split to make collars as well as texturing.
Use the interpolated spline. The reason why you use a interpolates spline is because you want them smooth, and no jagged edges, if you can help it.
We will have some jagged edges because of turning to low poly, though.