Any golf experts willing to coach me on Fluther?

Watching the British Open inspired me to ask this.
I am an average golfer. I don’t get to play much. But I’m a pretty good athlete, and I think I can improve by a several strokes if I can beat a bad and tough to break (for me) habit.
Right handed. I’m pretty tall 6’5” . I have a tendency to throw my left hip out instead of transferring weight from right to left foot in tempo with my downswing. When I do this, of course, I cut the ball and slice like murder.

I understand that there is nothing better than practicing at the range and playing. I get out as often as I can afford the time and money.

I need a drill I can do, in addition to going to the range. I am looking for a repetive drill that I can do over and over in the yard or the office or anywhere.
Any suggestions?