Ab workouts that will give results?

im a girl, 5'4" at 116lbs, and i have a flat stomach, i just want it to be toned and more muscular. i need a set plan that can give me results. ive been doing 4 sets of 25 crunches a night (just regular sit ups but half ones, not full ones), should they be giving me progress? will drinking protein shakes help at all after i work out? if anyone could take the time to give me a little nightly plan of ab workouts that could help me shape my tummmy i would greatly appreciate it, thank you