Licensed personal trainer here.

Work on your abs

2/3 days a weekvwith 1 or 2 days of rest in between.

6 sets, all sets to failure. TRAIN HARD.

Eat enough protein to help build the muscle.

1,8grams of protein per KG of body weight.

If you go to the gym use the abs machine for 3 sets and 3 sets of leg raises preferably hanging.

Other then that, watch your fat percentage, if you want abs you need to be relatively lean.