To be honest, it's pretty hard to do sight unseen. No standard pricing system.
I just listen to them, let them tell me what they want, and then do everything I can to make that happen. I might give some suggestions or insight along the way.
I took painting and decorating as a vocation in high school. Painted aircraft in the military. Painted custom homes for a variety of different home builders. I also have 10 years experience as a union commercial painter.