Spikes, I use different recon set ups depending on the map,
My set up is,
GOL Magnum / M95
X12 Optic sight
Extra Ammo
and the remote position sensor for the sight, cant remember the name
Mortar strike
M1911 Pistol
The GOL Magnum is the most accurate sniper rifle, but once I unlock magnum bullets I will use the M95 for its range and one shot one kill capability no matter where on the body you hit. I used the M24 up until the GOL magnum but sometimes using the QBU 88 with the x4 optic sight for built up maps.
When firing at range, on some of the large maps I need to aim 5mm above the targets head and up to 1" infront of them to hit them if they are running, but the more you practice the more familiar with deflection shots you will get.
Play the rush maps, I found as a sniper I could earn 5k points in a good match with 2 - 3k going on recon points the rest for bonuses to increase rank, lots of spotting and motion sensors and from kills will soon rocket the points up.
Think about your shape and silhouette, using cover behind a flat wall with your head above it will stand out at quite some distance, esp to other snipers. when on a hill dont be at the peak as it will cause your silhouette stand out against the back drop.
Avoid all the other snipers as it will draw the sniper hunters to them and you, fire a few shots and move around and avoid using the same spot because people will look for you if you start killing them a few times due to the kill cam.
I always will try to use un obvious places to shoot from and if I can try and shoot from the flanks as people tend to rush forwards and there is a less chance to be spotted or accidental walked into by someone. Things like on top of the hill that over looks the capture point etc is the usual spot to find someone sniping.
When shooting from the windows and doorways, stay as far back from the window as possible as it will make it harder for someone to spot, and don't forget your sniper rifle fires a tracer, so take a shot move away from the window completely and then take another shot..
hope this helps,
PS. playing Rush is a good way to level up fast, and sometimes when defending some maps, run around with the shotgun with the more powerful ammo and you soon get lots of kills too
I like most of the maps, the only one I dont like is the rush map with the small island on and the GOL Magnum is probably the best sniper rifle imho