What program will you use? I use 3ds Max, here is a tutorial using Max Character modeling, low poly, tutorial.

I start with a cube (or oil drum), its all personal preference. Sometimes I like to use the "symmetry" feature and make half a model so its the same on each side and have it fully visible in another window so its more like sculpting. It all depends on mood too. I use a couple basic "templates" that I have made, here is a pic of one of them [This is a Male template with advanced rig]: