How do you use turpentine?
I use white spirit or mineral spirits rather than turpentine. However, turpentine will still work for my technique. I use white spirit to clean my brushes as well as to thin my paint for upper layers when I need sharper details in the foreground. I give detailed information in each of my Online Art School tutorials for how to use and why, together with when I use white spirit, so that I can get the effect I want to achieve.