BLM is very simple to do well as, and easier to master than the other dps classes. There are a lot of little simple things that I always notice other BLMs not doing that are very useful:
-using sprint during fights (all mages in general, I rarely see this)
-running to the tank after pulling hate, or better yet before or during the GCD after a firestarter fire3
-using lethargy
-using apocatasasis/virus/eye for an eye (I'm guilty of this one)
-using raging/quelling/convert effectively on AoE nukes