First of all, we'll draw a hand in a simple position: with the palm open and the fingers equally distant.
I use a digitizing tablet, so I don't need to scan every single drawing.
The first step is drawing 2 circles: the diameter of the little one (the wrist) is about of the same length of the ray of the big one (the palm) .
Then trace the orizontal diameter of the big circle, and divide its higher half in 6 parts with 5 points.
Now, to create the structure of the fingers, draw 2 little lines (each one with the same length of the wrist's diameter) starting from the 2nd, 3rd, 4th and 5th point.
Draw a line that starts from A and that's perpendicular to the base of your sheet, and another one that starts from B and creates a 45° angle with the orizontal diameter of the palm circle.
In the meeting point of the 2 lines there's the C point: unite C with D.
This shape we've just drawn is the part where the thumb is connected with the palm.
Starting from the middle point of the AC line, draw 2 little lines, a bit shorter than the other phalanxes: they're the thumb.
Over each phalanx draw a rectangle: in the 5 external phalanxes the external side must to be drawn a little bit shorter, because it's the end of the fingers.
Now you can unit:
A and B
B and C with a curved line
C and D
D and E
F and A
Then draw 2 lines that start from E and F to create the wrist.
Pay attention to unit C with D and don't continue the curved line until X, because you'd create a weird round shape for the hand.
If you draw it correctly even the little finger will have the right length.
Now that you have the structure you can draw the definitive edges of your hand.
It's always a good idea observing ours own hands to copy details, for example the wrinkles of the skin.
Remember that exist a lot of different kind of fingers and hands, so you can draw them like you prefer, long or short or thin, and so on..
The most important thing is (in my opinion) the balance you're able to create so, even if the hand you're drawing is a bit weird, the result will be equally good if you menage to draw harmonious lines.
When you've made practice with the structure you can start drawing hands in different positions.
If the hand is in perspective, like in the example image, remember that the wrist is a sphere, then you'll see it always like a circle even if you change point of view.
The hand, instead, has a flattened shape, so the circle has to be drawn more like an oval.
In case you want to draw bended fingers, you have to draw them in perspective, then shorter, like in the example image. Try to imagine the external phalanxes like little sections of cones.
Lastly, to make your hands perfect, you've just to color them with your favourite technique, even using only flat colors (and maybe add them a body!).
This was the last step.
I hope this lesson could be useful.
Thank you for reading (n_n)