Make 10 holes in 1 in 1 tournament.
This by far is the most time consuming and frustrating achievement in the game. The only real tip I can give you is practice, practice, and some more practice. This is easiest done in the tournament Haunted Manor. Go into the practice mode and learn all of the trick shots; these are usually highlighted with sparkles. Once you get the hang of the course, just keep trying; you will eventually learn exactly where you have to line up the shots.
Haunted Manor guide
Manic Museum guide
Note: This MUST be done in one sitting. Unlike 3D Ultra Minigolf, if you quit out of the tournament, your progress toward the achievement will not save.