nice posts,
my tactic(s) -
Not everything/everyone is an immediate target, pick your shots, - don't draw attention to yourself. Wait until they have their back to you.
Gazala is a great map to practice mobile sniping, shot a few peeps, move on. There are lots of places to take vanatge points from.
Mersa Matruh is a good map to practice static sniping. Avoid the mosque tower it's a giveaway. There is a burnt out truck on the road from Matruh Mosque to Matruh Station, I have stayed there until out of ammo, rearmed (shot on the way back) returned later and basically stayed 99% of the map duration in that one spot with 27 kills.
^ With regards to that hiding place, of course every Pzr that passes it will fire a HE round at it, but there are 3 other places that I have had the same sucess with. Just don't feel like every map requires you to shoot and run.
Master the very long shot - the very very long shot, when the guy is almost a pixel in the fog, some may say this is cheating, but it's an art, the deviation of shot is there - as it would be in the real world, you need practice this over and over until you notice the pattern, Sfakia is the perfect palce to practice, grab the german rifle and park yourself at a point near the rearguard so you can see the monastray, infantry running up and down the hill between the command post and monastay are very hard to hit from a distance, infantry coming in and out of the monastary road will make excellent practice for long shots.