I've attached your image with my suggestions circled or highlighted, with notes on what I would personally do.
Note that these are suggestions, and if you think they are poor suggestions, then feel free to ignore them xD
Just a quick note about the trigger grip (the circled area I said needed more edges); I'm not entirely sure how you managed to get the edges to show up, but also look smooth. It may just be that (blender??) renders smoothed edges differently to maya in the perspective view, but I have a funny feeling you may have several edges grouped close together in those places. If that is the case, then all you need to do is spread out the edges, not add more.