One of the things to remember is that portrait sketching doesn't only require the practice of your hand but more importantly, training your eyes and your brain. It is helpful to look at different sketches to familiarize yourself with details. As I've mentioned, I'm not familiar with the different sketching techniques. What I realized was that every artist has his/her own way of doing their craft and there are certain methods that work on some artists which may not work for you. Truth is, there are no concrete rules when it comes to sketching. You will develop your own technique through practice and experience so this post will just give a rough guideline on different sketching techniques that can serve as your guide. Again, this is just a guide so don't hold back if you want to try something else.
