For now, my priority list looks something like this;

1. Someone who was fun to run with (fun in chat, playful, etc)
2. Someone who was helpful to newcomers
3. DPS if they didn't pull any weird stunts and were friendly.
OR someone who saved us from a near wipe by being awesome.
4. The healer of tank, depending on who I liked best.

Things that will make me give the commendation to others
1. Demanding/asking for recommendations
2. Being an impatient twat / being rude
3. DPS/Healer pulling before tank

Chances are that if you are the only person who bothered to say hi in the beginning and did nothing stupid, you will be the one who gets my recommendation.