The center of the circle on the sight is where the head should be. It's a hard weapon to do quick scopes with when you're just starting out. Hard scope popular lanes. After you shoot, you must hide. So stick close to cover. Remember to always aim head level and strafe. Have a trusty special. Preferably a sidearm or shotgun. You can practice in patrol. Dregs and vandals are about guardian height. I like running it with a second sniper. To practice, shoot, switch, shoot. When you are running the little caret that displays on your screen is the center of your bullet. You can use it to line up quick scopes off the sprint. I can give you many tips, but at the end of the day, it comes down to practice. You'll go into many matches and not get a single kill. Don't give up. Keep on practicing.