Hold the ball in the half court
Drive toward the basket with space
Trigger the alley-oop pass input to yourself
Use the right stick or pass button combo for a self alley-oop
Time the input before the defender closes
Catch the lob and finish at the rim
Practice the timing in 2KU or practice mode
Use a player with high dunk and vertical ratings
Make sure you have enough stamina
Do it near the paint for the best success rate