5 good tips for building great abs? Ok, here you go:
1) keep in mind that we all already have abs. The reason why your abs don't show is that they are hidden behind the belly fat, so your main focus needs to be on burning belly fat.
2) keep in mind that you don't lose fat on one isolated spot, you always gain/lose fat on your entire body. So this is not about training one particular area/muscle, but about burning the largest amount of fat possible.
3) so, you should start dieting and doing cardio exercises in order to burn excess fat. Cardio exercises with varying degrees of intensity (first slow, then fast, then super fast, then again fast - not always at the same intensity) are the best to burn fat
4) apart from burning fat, you should also tone and strengthen your abdominal muscles. Researches showed that hanging abs exercises (like with ab straps) are the most effective. However, they also are the most dangerous to your back, so you really need to follow instructions and make slow, controlled movements.
5) always train all your abdominal muscles, i.e. also your obliques (the muscles you use for twists) and the transversus abdominus (the so-called "corset"-muscle).
I hope that helps. I do have information on that on my blog, but I don't want you to think that I'm promoting my site here ;)