You say you're so-so fit. That leads me to believe that you only have a so-so training program. Are you doing aerobic exercise on a consistent basis? I don't mean three times a week for 30 minutes (the minimum recommendation). I mean five times a week for 45 minutes, sometimes longer. You should also be strength training at least twice a week, selecting exercises that recruit all of your large muscle groups. The aerobic (cardiovascular) activity burns calories while you're performing the exercise; that's why 45 minutes is more effective than 30 minutes. Strength training makes you leaner and helps burn more calories throughout the day.
Doing all this -- and let's not forget about limiting the fat in your diet -- will reduce the overall amount of fat on your body and in your midsection too. Treat your abdominals (stomach muscles) like any other muscle group and train them just two or three times a week. But train them hard. Here are five exercises that will help you get the abs of your dreams:

1. Sit on the floor with your knees bent and feet flat on the floor. Place your arms in front of you.
   
   
2. Contract you abdominal muscles and with a straight back slowly recline for 2 counts and then return to the start position for another 2 counts, then repeat for 8 - 12 times for 1 - 3 counts each time

99 WaysTo Keep Your Man Fit and Healthy