one finger on each lever, relax all muscles in your arms and hands so your reflexes can do their thing. Look ahead and where you want ur bike to go. SEE the line u want before making your bike go that way. If you ride a hardtail, you'll want to find the smoothes lines though each section. Use the brakes to avoid a the bike in front of you or coming to tech section. If you don't know the trail (especailly single track) brake early before a hard blind corner.
I ride with a Sony Minidisc player to keep the tempo up and my mind in a groove. Helps alot when riding solo and no one to talk to.