My stomach is pretty much flat but the very bottom of it isn't what I want it to be (it bumps out a little). What could I do to tighten up my lower stomach to make my belly look toned and flat.

Go to Lower Abdominal Exercises - More Important Than You Think! (http://www.abs-exercise-advice.com/lower-abdominal-exercises.html)

This site gives you excersies to do that will help, it helped me.