According to Zeven_NA, what is important as a light-tank player is to get early intell on the enemy team. As a lighttank-driver you are the eyes of the team.
What is your task on the map is to see, where does my team take the most damage? What can I do to help?
To avoid arty hits, is to anticipate where is the most likely place for artillery to be? The arty's reach, in World of tanks, matches bishop, castle and Queen's moves in a game of chess, if that's a game you have played.
With your team, you got to win some place of the map. Playing light tanks is team-depending, but not as in, sit back and let your team do all the work for you.
Learn to know when to snap the shot, and when to take time to aim.
Learn to know what to fear.