Check the "Working With" pages for the different classes and look at the "What Xs want non-Xs to know". Always cast Mark of the Wild/Gift of the Wild on your party members, it saves lives! Only cast Thorns on people who can handle the additional aggro it gives them. Remind people that if they don't want thorns, they can remove the buff by right-clicking it. It's common practice if you meet another buffing class in the wild to 'trade' buffs, so give a passing priest, mage or paladin a Mark of the Wild and you'll usually get stamina, intellect or a blessing in return.