You can basically see by the polygons that the edgeflow isn't good. It has to look connected unlike it is now, try to make the lines look smooth from a distance. It's hard to explain, and yes most low poly models have a bad edgeflow, but in your case, it's visible without a wireframe.
http://tobiasolofsson.com/wp-content...me-800x453.png
there you can see what I mean with good edgeflow, the lines on the handle are "smooth" and follow one another. Ofcourse this model has more faces then yours, but you get the idea.
As for the trigger, once again it doesn't make sense, also look at the example, this model has a bigger area. Try to make a box of a human size trigger finger, and put in there, you'll see.
