You need to fake soft shadows on your texture. Lighting is key to making a texture look good. If your modeling program supports it, render the gun with light bouncing on. I gaurentee you it will look much better already, because human eyes are very keen to things that don't look lit properly. Your texture also has some tiling errors when it hits corners, probably due to the fact that it's hard to make one edge line up perfectly with another if they aren't touching in a paint program. Try copying one edge and pasting it mirror onto the other, and then fading it in to the regular texture. That way the two edges will line up with mirror textures and it will look seamless.
For your grip, try making that an inner bevel for the wood, not an outer bevel. And also reduce the contrast between shadow / highlight on all bevels, they look a bit extreme. The flat screws on the grip look ok, but I would probably replace them with more realistic looking ones.
Might want to add a hammer in the back of the model too. And I think you should fix up the trigger, it looks a little boxy. And maybe add a dark bar on the texture where the trigger meets the gun, so it looks like it has room to slide.
I also think it still needs to be thicker. Don't forget a clip is suppsed to go into the bottom of the gun. So you need room for the thickness of a bullt / casing, the clip itself, the mechanism to get the clip in, and the actual body of the gun.
