I’m 5’11 and 175 pounds and I have a beer belly, yet I barely drink. I do crunches and it still doesn’t go away. I need a diet that will make the fat in my stomach go away but will not let me drop weight and help me build more muscle. Damn, I now fit the over-weight population of America, and I am not really fat I am a mix between slim build with a big stomach. And this fat is destroying my body, making stretch marks all over my body and my chest is flabby and I bench press.
Try aerobic exercises like swimming or running but if you are a yank its probably cold over there now so mabey go for the running.
Most effective way to get your abs to show is to lose fat. That is proper diet and plenty of cardio (yes plenty). Like 3-5 days a week of cardio. Just run and jog and hop and stuff. And keep up with the sit-ups and crunches. Chances are you have a 6-pack, it’s just behind all that fat.