Good ball is a MUST, Nike or Srixon have the best.
My local course has accual Greens and Flags on the range and as they moving the teeing ground back and forth they have a sign that says 147 to RED or 175 to White. Its a great set up, I love it.
Also you have to have good mats, Nothing worse then going to a range and having your clubs boucing off it and leaving ugly green scraps on your clubs.
Shortgame is a must (2 greens 1 for chipping 1 for putting)
Have a gimmic, Put a large glass door about 250 out in the middle if someone breaks it they get Range balls for a year or a few dozen balls or something like that.
Have fun targets, A range around here has some nets about 80 yards out to hit High wedges into and some other fun targets to hit at.
A Mini-putt is always a good addition to anywhere.
Quality Clubs in the proShop let people demo them on the range.
Snack Bar (Or at least a coke machine)
Club repair in proshop