How long does it take to flatten your stomach up if you're already half decent?

How long does it take and what are your favorite workouts to prep for Summer? I'm in the general ballpark of my ideal figure...but it's natural with only the occasional work out and a bit of walking and jogging. I want some of the most effective ways you know to slim down a little more for bathing suit season.

And as related side questions...butt lift and arm slimming. Not too much toning, just slimming really.
Updates
+1 y
I wish I could have chosen more 'most helpful' because this question doesn't have really only one right answer. Thanks for all of your suggestions. :)
How long does it take to flatten your stomach up if you're already half decent?
Post Opinion