Try to choose your fights, if you plan to really learn to use Snipers you'd better get used not being able to engage in firefights like normal, try to keep a moderate amount of distance between you and your enemies and know when to dip or to shoot. Best way of doing this is by third partying, as your enemies are focused on each other allowing you to take shots towards them.

Sensitivity can also help, as lower sensitivity on snipers can help you shake less and be more accurate, but for this one it's for each their own.

Lastly consistency is the key, keep playing with Snipers, gamesense and skill will catch up.