How do I model humanoids
strange question, even without a questionmark. it is so vague, it can’t be answered easily. but since you didn’t spend any time at making some specifications, i don’t see why i should spend another half an hour to answer, considering everything you may have meant (which is a LOT).
sorry. For instance , When I create the body from cubes and subsurf it, it just has rounded edges and is still cubic.And when I model the torso, it looks like a bean.Sorry for the hasty question.
no worries. i think you’ll need a higher subdivided mesh then, which defines the body more precisely. if you are looking for a good tut on body modelling, go to 3dtotal.com and look for the joan of arc tutorial (in the freebies section). it’s for max, but can be easily done inblender, too.
subsurfing still is only a way to smooth out geometry, it doesn’t add details by itself.
How can I get a picture file into blender like that for a reference image?
:x :x
The Search option in the forum is an invaluable tool. How many times has this been asked?
Now that I’m done… 
In the 3D window, View -> Background Image.
-Laurifer