Itīd be better if you post the entire icon.

Hyiorinmaru wrote:

Right now i am only concentrating on the shirt.

Not to sound suspicious but they are a little right.
Posting a part, piece, or bit of an icon wont show comparison compared to the rest of it.
So, shading, detail and whatnot could look good as a separate section, but then once added to the whole icon itself could look funky.
It's a nicely done shirt, but my only problem is the figure of the person itself.
The 'box' look from when the underarms end to the start of the hips.
Should maybe add some more width to the lower/middle chest area.