When mixing your paint, how do you get it to the right consistency for the task at hand? How do you know exactly what the right mixture is? For a long time, for me the answers to those two questions were "mix in water with a brush" and "not a clue, I'll tell you when I see it".
Over the last few sessions, I've been giving something new a go. Well not new, but new to me. I've been using a pipette :)