Hummm... looking at those two pictures, I've made a conclusion.
I'm guessing that you just start drawing without any planning. As in, you draw an eye or a nose first, then just work from there. And that's why the shape of the head (in the first one) is kinda lumpy looking, and some things are a bit unproportions.
To help all that, drawing basic shapes and lines first is a good idea. Like, if you plan on drawing a head, here's what you'd want to do first:

Firstly, draw an oval shape for the head, then add the lines.
The vertical magenta line divides the face into two separate halves. Use this to keep each side of the face even and balanced.
The red line goes across the eye-line. The eye-line is right in the middle—between the top of the skull and the bottom of the chin.
Halfway between the red line (eye line) and the bottom of the chin is the blue line—where the bottom of the nose is.
Then, a little less than halfway between the nose-line and the bottom of the chin is the mouth-line.
Also note the yellow lines that go up and down—they line up at the corners of the mouth, up to the pupil of the eye.
Once you have everything in the right place you can start making your own adjustments to make it look like the face you wanted to create.
3nodding There's also a lot of tutorials out there that'll help you with profile drawing.