Make 10 holes in 1 in 1 tournament.
This is probably the hardest trophy in the game, but keep practicing and you'll eventually become an Ace on at least one course. This can be done on any of the three default courses. It will not unlock if you make an 18 hole custom course.
Note: If you select Exit Tournament at any time and then load the same tournament from the menu, it appears to reset your hole-in-one count. So you will need to get 10 hole-in-ones after loading the tournament before the trophy will unlock. It's best to just not use Exit Tournament while going for this trophy.
I chose to do this on Haunted Manor as it has the most holes with easy shortcuts. If you're struggling with any of the holes on that course, a complete guide can be found here: