Another good indicator is how long you currently take. You may not be doing the right things during the preshot, but chances are the amount of time you take is comfortable for you. Have a friend time you on several shots and use that as a starting point. Consider adding a rehearsal swing and a mental cue to help you let go of control. And remember, stay in motion over the ball, whether you waggle the club, readjust your stance, or whatever.
Movement keeps tension from setting in.
Other details, such as how you take your stance and how many times you look at the target, are up to you and your instructor. But keep it simple. Resist the temptation to give yourself that last-second lesson. Pick one concise thought and go with it. Once you've built in the basic elements, add to them cautiously, keeping track of time.