What's A Good Tactic For Doing Well On A Team Sharpshooter On XBox 360's Rainbow Six?

First of all, wear dark clothing and don't walk in front of the windows.  Use a sniper rifle, the PSG is not best but you only have to reload every five shots, whereas the best rifle needs reloading every shot (and re-targetting thus).

Hide in the shadows at the back of the spawns and look out of the windows.  People hide behind crates and boxes, but generally, with the x12 scope on, you'll see them.  Don't move unless you have to do so.  It just makes you a target.

In Spawn B, get behind the long box near the left window, crouch around the far left edge, you're almost but not quite invisible there.

Don't stay in the same place.  It's snipe and move, snipe and move.  You can also snipe from the porch, but be aware of people coming up the ramps to your left or charging the spawn.

If you play spawn attacks, watch your ass