Think and check first, then shoot

especially in the big open maps.
Alot of people run around and just shoot anything that moves or just chuck nades everywhere!
Mistakes do happen though from time to time though, I have like 2 or 3 teamkills in 20 something games.....if you teamkill, first off apologize!!!
A perfect example of an error/teamkill I can think of is yesterday in citadel, I was having a shootout with a seal thru a doorway. The seal and I had criss crossed the doorway a couple times and we were probably both getting low on health and one of us was about to go down. One of my teamates took him out by entering the gunfight from the room the seal was in. I didn't see the seal go down nor did I see my teamate enter the other room and after he takes out the seal, blam, my teamate bolts thru the door the seal and I were just battling thru.
In that situation you react so fast its hard to stop it. My teamate should have slowed down after he finished off the seal a bit before charging thru the doorway......h3ll I thought it was the damm seal and a descision had to be made in split second...
