The first three cards you stick into the fray should all be medium strength. That way you're best placed to combat anything that your foe throws at you. Try to lead with something like a 5, 6, 7. Not only does that mean you've got some power on the board without chucking out your 8s and 9s, it also means that if you do take a bad hit in the first couple of rounds, you've not lost anything that could change the game later on.