There's always some danger to getting into an online game late. Some people have already logged 100+ hours and made thousands of kills, memorized every nook and crany of the map and honed their aim and control sensistivity to perfection.Originally Posted by Trulen
As a general rule, unranked games will have less skilled players. That's a pretty good place to get better.
Otherwise, you can actually look at the people on a particular server and check their ranks. Then avoid servers with highly ranked players. That should make it a little less frustrating.