Life drawing. That’s the best way to learn how to draw figures and the human body. If you can, go to a course where you can be tutored on the subject. If not possible try to sit your family members or friends down and draw them. Keep a sketchbook with you at all times and draw anything and everything whenever and wherever you can. Sit down in a public spot and draw people around you. Draw statues, draw buildings, draw animals and trees. These will teach you more than anything.
There are some books out there that can direct you in the right direction too. The Andrew Loomis books are fantastic for example. Especially “Figure Drawing For All It’s Worth” will help you a lot.