That's not a good habit to get into. I can suggest books on learning to draw the face, but you'll never learn if you don't practice. I'm still terrible at alot of things, but I still draw them. I'm still learning and I wont hide that. The more I draw things I can't draw, the better I get at it. No point practicing what you're good at, right?
Another tip- flip your picture horizontally and see if it looks funny. If it look correct both ways then your picture is balanced. You'll see mistakes easier this way cause it takes your mind by surprise. IT's a technique the pro use.