The only thing i can add is just to draw from life. draw your hands in the mirror, draw your friends holding different things in their hands, all that jazz.
Practice, practice, practice man. If this crap was easy, everyone would be doing it. Just work hard, and it will pay off.
Also, takling a peek at an anatomy book wouldn't hurt either. Sometimes knowing how things work gives us a better, more grounded understanding of what we're drawing.
Seriously though, just pester your friends a family to hold stuff (everything from toy guns to cups to cigarettes) and you'll be infinitely more comfortable drawing hands in no time