A trainer told me that I only have to train abs with a couple exercises once or twice a week with 10–15 reps and some added weight, but my waist actually seems like it is getting bigger and the fat is still covering it.

I have said it before and I will say it again: The basic rules for lean muscle building do not always apply to abdominals. Yes, it is true that you can develop your abs like other muscle groups by training the area once or twice a week with 6–8 sets of 10–15 reps, but that does not mean you are guaranteed to get a V-tapered six-pack. For most of us, it takes a high- quality diet of approximately 40% protein, 40% carbs and 20% fat, along with 20 - 45 minutes of cardio (preferably in the morning on an empty stomach).

Many of us need to use what I call an "overtraining principle" to get that desired look. The idea is not to build a larger waist with bigger, thicker abdominals and obliques. The goal is to have tighter, more defined muscles that appear hard and ripped.

What is overtraining? It is exercising a body part intensely and frequently, to the point where the muscle does not fully recover. This causes it to become harder but without much growth. Start training abdominals every other day or two days in a row with one day off. Increase the number of reps to 25 - 50 per set. Do giant sets of 4 - 5 exercises with no rest and using no weight other than your own. Control your movements, working for a full stretch and contraction.