What exactly do you mean? The face, the body, the proportions?
Basically, good drawings only come from practice, and each person has his/her own style, so maybe you think your drawings are bad, but it's actually different, not bad. I thought my drawings suck, but then compared to other people, and talked about it, and in the end i accepted my drawings as "my style". It's rough, looks little blocky, but hey, you can tell if that's a person or a tree. I still don't like them, but what am i gonna do? Practice and more practice.
If you want you can get some guides, like the face division, that let's you put the eyes/mouth/nose proportionally correct, by spliting the face in 3 horizontal parts, and 1 time vertically. Other things like body proportion, like the face/palm (no pun intended) proportion. Then the easiest way to do bodies is looking at yourself in a mirror, what better example than yourself to see proportions? Like: arms go pass the hips, legs and arms are almost the same lenght, i think the torso is 2 heads, etc.
Drawing body parts as "bubbles", to make a puppet-looking person first, and then drawing on top and erasing the "puppet", is a very good way of drawing different poses and articulations.
But, even with all that, and more, it's just plain practice. Want to draw people better? Just draw people, again and again. Try making them different, changing faces, positions, height, weight, etc.
Practice makes perfect!