Practice makes perfect. Play some target shooting games. And when you're feeling good at it, try downloading some beginner's FPS game like the good old Call of Duty. If you are really getting good at it try installing Ghost Recon Phantoms. It's an online FPS with no raging kids and seeing hackers there are rare. Plus, the game is still alive because lots of new stuff are being added and it has a fair currency. Like, buy one item using, gold or cash. I like it. Also this game has a shooting range which means you can practice shooting at targets.