One thing that I KEEP forgetting is to draw light..at least that works for me. But I often gets so caught up in just drawing that I draw really hard. The problem is that when I put down a line that's wrong it gets harder to "hide" it (since I don't erase). It also allows you to go back in and "stress" some lines that are important.
2 minutes below. You can see in the top ones that I used the brush too hard, Second last image looked better since I had the opportunity to make an "informed" decision after gliding across with a light touch.