micoach is all you need to get the results you want.
I'm a 10-12 and bought the medium but probably should have bought the small as these are slghtly loose. They're a good length in that they're not too short unlike some of the tennis dresses and other tennis skorts I have seen which are fine when you're in your 20s but approaching mid-30s I'd rather not be flashing my bottom. What I particularly like about these skorts is the ball pockets as it's much nicer to have somewhere specific to keep the balls as opposed to tucking them under the shorts.
Recently I lost a lot of weight and this dress was my reward. I am 5'3" and 133 lbs and the small fit me well. I like the dress design because it is classy but is long enough that my glutes were covered (not too short). It is light and easy to move in while playing singles or doubles. I received a lot of compliments on this dress which I was very grateful to hear. I hope you enjoy this dress as much as I have.