Every death gives the other team points and a brief numerical advantage. The more negative players on one side the greater the chance you lose. If you're contributing five kills for every ten deaths then you need to gain at least five flag captures to make up for that and that barely puts you at a 1:1 points ratio. If you're rocking a 0.5 k/d I don't think there is much chance you're capable of that. The key to contributing to a team is staying alive. That may mean playing more cautiously than you like to but it is more effective in the long run. People need to know when to back away from a firefight and learn how to keep close to cover. The first few shots in any exchange are invaluable, it is important you give yourself every chance to be the one landing them. Stay close to your team but hang at the back and pay attention to your sensor.