Learn to draw by sight is a skill that requires years of practice and study. However, by understanding the principles of "Relative Drawing" you can quickly pick up on this method for more precise artwork without using a grid. I do not recommend this method, because it isn't very precise. I am actually no good at it, but find the concepts are important for drawing in general. Use this method with the grid method and you have an awesome combination.
- how to draw a face