Speaking of belly: I was not very big and my metabolism was pretty good, but I had a little belly too... it is definitely not a very attractive feature for both men and women.
I highly recommend eating a good diet, and remember that healthy ≠ starving. Eating had a larger impact than exercising, but I still exercise too. I would make more specific recommendations for you, but I think there really are no secrets so far as losing a belly and getting into a more desirable shape.... cut simple sugars as much as you can, pick healthy alternatives instead of starving yourself, and exercise a little bit. HRT is pretty magical, but it can't do everything.
I hope this may be motivating, or at least I feel good about it:
~ October 2014 (~ 165 lbs.)

(My face is blatantly showing, and the shirt gives away my location. I cropped and cover them out.)
January 2016 (today) (134 lbs.)

(Side to show proportions)

(Left side is resting the stomach muscles, and right side is flexing them. I show a comparison to emphasize that it is not very masculine)