I don't have experience with the warrior tank but have gotten a paladin tank to 50. The main stat to invest in as a tank is vitality to boost your hp as high as possible so you can stand against boss fights longer. Your gear will help round out your other stats that'll help you. Positioning is important as a tank as that can determine how much damage the others in the group will take. Holding aggro is vital too, so remember to throw an extra flash or something that is heavy aggro from time to time in a boss fight to keep the focus on you. Practice makes perfect too. Hope this helps some.