Make sure you can use any blaster and be good with it. You never know when you might need to be more than a sniper.
Basically, where you can exit and enter the sniper post without blowing your cover or giving away your hiding spot. If you’re found, don’t shout. Enemies can find you easily, just use a backup that has more than a shot and doesn’t jam a lot. Cover and Concealment are Key
Never stand in a corner for more than 3 shots. If you do, and you get found, you will get destroyed! (This is somewhat dependent on your playing style. You might want to draw your enemies in, and then take out a bunch of them before moving. )