All I can do is give you this link.
I'm not that good at telling people that kind of thing.
link

I can't draw people, either. Stick with what you can do.

Practice back in the past i mainly could only draw animals then i started drawing comic book and characters and things like that and i worked my way up to people that look real now i can draw just about anyone and anything which I'm often drawing movie and comic characters that's usually what i get caught drawing in class
you could do art class's but if your like me and have an unorthodox style and draw things better your way than by the books Then i wouldn't recommend it; you could just look at some how to draw books and videos to get an idea then go about it
just try hard stick to it and practice I'm sure you'll get it some day
good luck and happy drawing

trouble with proportions is quite common amongst even the best artist in the world try for the eyes and nose
in-between the eyes there should be room for a third thats one proportion and then if you were to draw a triangle under neath the nose where the ends hit a point is where you should draw the mouth
hope that helps it didn't do me much help till recently it started making sence and now the faces are doing better also the nose isn't a bunch of lines its just primarily shading in a matter of fact its primarily shading