1 year post TT. I want more of an innie belly button. Can you tell me techniques I could use? Does the marble technique work?

I always thought that plastic surgeons were the only ones who actually cared about the shape/ size/ appearance of the belly button. But no, some patients do too! I reckon overall it's probably a good sign if you're concerned with your belly button after a tummy tuck...it hopefully means the scar/ shape/ waist/ flatness etc are all ok with you. 
But as for what you can do, not much I suspect. Feel free to try the marble trick, stranger things have happened. But otherwise you may need some touch up surgery to pull the base of the umbi inwards. This generally works reasonable well, except in super skinny patients who just don't have any body fat around the umbilicus.
Good luck.

One year after a tummy tuck, it is unlikely that your belly button will change. You may benefit from a local revision procedure to adjust your belly button size and depth to give it more of an innie look. Keep in mind, the skinnier you are, the less likely your belly button will be an innie simply because it has nowhere deep to go! Hope this helps.Johnson C. Lee, MD
Board-Certified Plastic Surgeon