Familiarize yourself with this map; there are a LOT of nice, dark, out of the way areas for sniping, you just need to find them.
Be sure you have good Recon! Don't let the other team sneak behind you and lead the VIP to victory while you are fighting another less important battle.
Don't kill the VIP! This being said, grenades will make the VIP stop following if they land close to him.
Use the shadows in this level to your advantage.
A good Recon on the terrorist side can sneak into the sugar factory and around into the tunnel area where the other team likes to snipe. If you can get there, you can usually slaughter their sniper(s) with ease.