Just a few things I'd like to call to your attention:
- Luke keeps check on his fundamentals. Little things like alignment and how far you stand from the ball are things that can get out of whack a little at a time without you even noticing it.
- He doesn't determine his ball based on his foot position. Rather, he places the ball based on his upper body -- typically between his left armpit and his left eye -- which is closer to where his arms actually are. It's too easy to get your upper body tilted and have the ball in a place where you can't hit it.
- Luke specifically says that he cups his left wrist at the top of his swing. That's probably not a good idea for most of you since it can cause a slice. Luke has a specific problem that this wrist position fixes.
- Note that he tries to keep his knees flexed and his hips level at impact. This helps him keep from leaning backward and hitting that push shot he mentions.