Some more notes, very randomly presented:

For getting started in WotLK content, I found the Nexus to be easier than Utgarde Keep. Maybe it was just me, but the bosses seemed tougher for a multi-hunter team in UK. Nexus is also non-linear, so you can try some of the bosses and skip one if you can't finish it. You can also clear 90% of the trash in the dungeon for XP gain without even worrying about killing the bosses. The last boss in Nexus may give you grief at first, but again, she's totally skippable if you've cleared everything else. Do what you can, leave, and reset. It lends itself to a nice loop configuration, so you don't waste a lot of time running.

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Definitely put a pet on each target if you are struggling with the trash pulls. I use focus targeting for all my DPS spells, but I will pre-assign targets before a tough pull by using 4 keys and then a fifth "launch pets" key. It's something like this:

For each hunter (I have these bound to U,I,O,P, and only one bound for each account):

/target focustarget
/cast Hunter's Mark

I can target the mobs in the pack with my main, and each hunter will change their target to the current target and cast Hunter's Mark on it. This macro does NOTHING else, and the keys are tied to this macro one per account. Hunter's mark is both useful and a visual confirmation that you have each alt properly targeting the mobs. (If you go too quickly, you'll see a lagging hunter cast HM on top of the previous mob).

I then release the gorillas with a shared /petattack macro. All four will run out to a different target. You can get fancy and add a /cast [target=playerpet] Misdirection in there as well, or bind a pulling shot with an alt modifier so that the hunters pull the pack with a normal shot as the pets charge out. This last thing is really handy to keep your pets from aggroing more than one group, especially with fear-ing mobs.

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As you get better geared and trash isn't a challenge, I just put all pets on the first mob that I want dead and let Thunderstomp aggro the rest. You will get some natural variation in TS damage and generally spread out aggro so that no gorilla has more than 2 mobs on it.

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Traps... I have traps on round robin and occasionally lay down an emergency trap or two in front of my healer. This is rarely needed. More often, I don't lay down any traps at the start of a pull and will just throw one down if my healer (who's the main) gets an aggro warning. Again, rarely needed with TS doing so much great AoE aggro. Now that I'm 80, I will occasionally toss out some Freezing Arrow-ed traps on a character or two just for fun. I don't use a DPS trap at all, even though there's probably some argument that 4xAoE traps would help DPS. I just want the fight happening way out there (*wiggles finger*) in front of the healer+hunter pack, and not close up.

4xDisengage is helpful. I use it in a variety of instance settings.

For a strong BM spec, consider using Aspect of the Beast. As your gear improves, its benefit gets even better. TS does so much damage that the last mob or two in a 4-pull is nearly dead from pet AoE by the time I get to it with the hunters.

4xVolley may be tedious to click to set up and it's hard to keep your healer on task, but there are some situations where it may be helpful to mow through stuff.

Fef-- Definitely spec Improved Rejuvenation and Improved Regrowth on your druid as you're leveling. Improved Rejuv on a pet is amazing...

Speccing improved revive pet (or whatever shortens your pet rez cast time) is VERY nice for instance running. 4sec battle rez on any pet that goes down. There have been a few boss fights where the pet went through 6-7 of my pets during the course of the fight.

If I think of any other tidbits, I'll pass them along.