So far you've got some pretty good advice, I'll add my .02
As already mentioned a couple things for the shadows are
1 - Have subject facing the sun, usually takes care of the shadows but sometimes gets your subject squinting and not looking relaxed.
2 - Use your flash as a fill flash to take care of shadows. While this does a good job it is not a cure-all, depending on your natural lighting conditions you should shoot some with and some without the flash and sort out the ones you prefer later.
3 - Choose a shaded spot for taking pics.
4 - All the above.
Other critiques would be...
1 - To be closer to your subject, you have too much foreground in the pic.
2 - Framing, I like firedivers frame example for framing other than I would try to have a little more space above the gun barrell on top. For photos I usually give myself a little extra room for me to crop it down later in the computer as opposed to trying to hit the frameing perfect and find out later I accidently cut something out that I need.
3 - In reference to framing, always to horizontal & vertical formats of the same shot - that way if your submitting it for a publication or website the editor can choose what fits his format the best.