Greetings, young level 20 hunter! You've just got Freezing Trap which is going to make your life easier!
You may have heard of a mythical thing we like to call "Chain-trapping", i.e., chaining your traps together such that you can keep a mob trapped indefinitely. Now, that is indeed what you are aiming for eventually, but keep in mind that it's not exactly something you'll be doing very much before you get Freezing Trap Rank 3 at level 60. Your traps simply will not last as long. At this point, if somebody asks you to chain-trap in Deadmines or WC, there is no shame in telling them that it's not a good idea.
So what are you going to be using lowbie traps for, then? When solo'ing and leveling, it's very handy for keeping extra mobs out of your hair.
An example situation would go something like this:
You see two mobs standing next to each other. You send your pet in on one. They both aggro on your pet. Now the problem is, that if you just continue this scenario as is (you and your pet both attacking one target), it's very possible that the second guy will pick up on your Mend Pet threat and come running for you.
So what do you do in advance of this situation? You lay a Freezing Trap down at your feet right about the time you send your pet in. If Second Guy comes running for you, he will run into your trap. Usually you can keep him trapped long enough to finish up your first guy.
If your pet is taking a lot of damage you can also purposefully pull one guy into your trap by way of Multi-Shot: that will alert Second Guy to your presence and get him to come running into your trap, so he is off of your pet.
A trap can also be quite handy to give your or your pet some recovery time before you finish up the fight. If you are already both quite wounded after a large pull and you have one guy left, you can trap that guy, pop up a Mend Pet and throw a bandage on yourself, and then finish up the guy in your trap.
Overall, Freezing Traps are one of the most useful tools you have at your disposal as a hunter. Always keep them in mind. They are your main form of crowd control and as you level and get better ranks of Freezing Trap and practice with them... you will learn that a hunter who knows how to trap is a hunter that everybody loves.
Things to Keep in Mind:
-Your trap needs two seconds of "arming time", that is, if you lay down your trap right as a guy is on top of you, you will have to take a hit or two for a couple seconds.
-Once you lay down a trap, it will be active for one minute (before it disappears).
-Damage done to the trapped target will break the trap. That includes DoTs such as Serpent Sting. If you suspect you may possibly be trapping, it is a good idea not to use Serpent Sting. You can, however, use things like Distracting Shot because it doesn't cause damage and will not break your trap.
-Traps have a chance to break early. It's not your fault when that happens, it's just something that you will have to deal with sometimes. Traps can also be resisted entirely, and there are some mobs that are immune to traps.
-Remember to put some space between the trap and you, or the mob will still hit you before getting frozen. Not a big deal when out in the open field, but rather more important in a raid or heroic.
-It is very possible to accidentally break your own trap via Auto Shot. If you have this problem a lot, you may want to look into a Pull Shot macro.
Freezing Traps can be improved (along with all other traps) via Survival talents, which will make chain-trapping easier, but you certainly do not need those talents to be a successful trapper. All it takes a little practice and a little timing. Eventually, as you gain higher ranks of your Freezing Trap, you will be able to start practicing your chain-trapping; but until then, just get a feel for when and how to use your trap.
In closing, I leave you with "Tawyn's Trapathon", a movie I made several months ago (and which you may have already seen, but hey!):
Yes, it has its nub moments, but I wasn't going for anything particularly fancy at the time, I was just FRAPSing one of my routine farming sessions. =P
And I will see you on our next installment of SYWtPaH, when we get to level 30!