I always, ALWAYS use stick figures. Because I, unlike some lucky people out there, cannot judge the size and position of my picture beforehand, and always end up going off the page or getting porportions wrong if I do. I think the stick figure is very useful, especially in complex poses.
The key is to establish the size and relation of all body parts to each other, then put them all together. Sometimes, I put ovals on top of the stick frame to get the muscle structure.
My key advice is this: Don't cut out part of the body because you're bad at it. I used to do this, and of course I never improved until I started drawing them. For example, I'd always draw the feet buried in grass, or the hands behind the back or in pockets. DON'T!! It doesn't matter if drawing ugly hands or feet ruins an otherwise perfect picture, because it's the only way to ever get good at them. (and I'm using hands and feet as an example - those are just my problem areas)
Likewise, don't always draw the same position all the time. Try some crazy positions. It'll help you learn your anatomy better, and become good at foreshortening. Also, you should develop a system for yourself- steps you use for drawing all the time. It will make things so much easier. My steps are:
a) Stick figure
b) Define the muscles
c) Flesh the figure in
d) Add clothing
e) Erase uneeded lines
f) detail/color/whatever
I hope those things help... I learned pretty much all that through experience, except maybe the way I draw stick figures, which I got from the tutorials at
http://www.bakaneko.com (great site! helpful!) Anyway, I've attached an example of one of my stick figures, because I for one am a visual learner and all this text would be meaningless to me without some visual aid. I don't know if you're like that or not...
Oh!! Speaking of the attachment, drawing on lined paper is very helpful! Its easier to get things symmetrical that way. I practice on notebook paper all the time. ^^ (And sorry if I ramble- art is a topic I get excited about ^^;;)