Just keep doing your bit - selling and despatching in good time.
Forget feedback. Don't chase it - that will lose you more than it will gain you. With my buying hat on, I avoid sellers who chase feedback, and I certainly don't give them any. You'll get enough without chasing it.
Mark items as despatched when they are despatched, and add tracking details if appropriate. The buyers can see that - they don't want a pen-friend.