No 1. mounting in combat
It gets really annoying, you ride along and suddenly something hits you, you daze and dismount, but your pet also summons, a neat trick is to feign death, then once that you will exit combat and your pet will go aggro, then you simply stand up, mount, your pet vanishes and the mob runs off
No 2. Snake Traps
Snake traps are very useful as they deliver a number of different Poison Dots, but if you use them in instances you run a risk as if you place the trap near a un pulled group, chances are the snakes will slither over the other group, so take caution and watch the distance of the trap.
No 3. Freezing trap is your friend
Whether you need it or not, keep a freezing trap at your feet at all times, always useful for areas of gathered mobs and in case your pet dies. Beat mastery hunters have a easier time with this as they run a less risk of pulling the mob, so you shouldn't worry about freezing your target