Go to Play. Select Xbox Live. Player Match, Create Match, Private Match, Match Play. Sign in all the controllers you have. 4 works best if you have them. They can all be guests. Either course works, but Caribbean works better. Random 4 holes.
Here's where my solution differs. Rather than have all your controllers play through the entire match, you can have them whiff. The down side is that they have to whiff 10 times, but at least you don't have to have them make the putt (and you're assured that they don't win the hole). The easiest way is to press the A button three times in a row. Do it for all your guests, and they'll drop out of the hole, leaving you to finish it.
You need 3 controllers for the first 3 matches, but on the fourth, you only need one other controller. (Alternatively, if you have fewer controllers, just make sure that you beat 10 guests. Two controllers = 10 matches, three = 5 matches.)
I found it easier to have the other controllers whiff, but that's me. You don't have to worry about which controller is which, and you don't have to worry about losing to them.