Hands are my favorite part of the body to draw. A lot of people hate them because they're hard so complicated - but that's why I love them; it's a complexity that leads to expressiveness! Here's the methods I've been using for years. I don't always work hands out in this much detail, but when I need to, it's there - and my faster hand drawings are informed by lots of time spent with this level of attention to the construction.

Remember, you always have a hand model nearby (assuming you haven't had a nasty accident); if you're at a loss for what to draw, put your free hand in a pose and draw it. Study, practice, experiment with construction.

If you're wondering, I never use 'sausage' construction for hands because I feel the orientation of the fingers is very important; block construction constantly reminds you that they can't twist on their own.

(This is an old tutorial I drew out several years ago. I still work the same way.)