alright, if u really want ur abs to show, u need to get rid of the fat first obviously. do interval training: sprint for 30 seconds, jog for a minute and then do it again like ten times or as long as you can go. for situps, the best way to build ur abs is to use heavier weights and lower reps because of the type of muscle fiber your abs are. use a decline bench on the highest incline setting and grab a ten pound weight and put it behind your head, not on ur chest, gotta be behind the head. do 3 sets of 10-12 reps. then use the same bench and weight, but hold it out with your arms fully extended. as you go down, move the weight from straight out in front of you to your side (twist your torso) but keep your arms straight out the whole time. 3 sets, 10-12 reps doing one side at a time(go to the right ten times, then the left ten times is one set). if u have a friend, do some medicine ball tosses on the incline bench too and have him throw your legs down or just do leg lifts. then go to a tricep pull down machine and hold the rope things behind your head while you're on your knees and crunch down so u feel it in the top of your abs, 3 sets, 15 reps. last, find a mat and get in a push-up position on your elbows and hold yourself flat for 2 minutes (repeat until ur really hurting). periodically throughout the day, tense your abs up for about a minute just to keep them in check. now just don't eat a lot of sugar, carbs or high fructose corn syrup products and you should be set.