Horde's main thing is they hurt in BGs. Then again, where my 70 horde is, over on Gnomeragan (which might not be representative of all realms); end game raides was such that AQ wasn't even opened until this year, and I heard suggestion Bliz might have finally just opened it for us, because people horde side just never got to it. Allegedly (but not alliance on that realm, so don't know), they completed the necessary steps.
On the other hand, it might be better he asks here, rather then on WoW forums. If he asks there, he might get contacted; but the questions will be things that as a still lvling character he wouldn't be prepared for. Things ranging from "what's your kara attunement status", down to his build and number of epics. A lvling char might not have an end game build, and in some cases, lvling as a tank, healer, whatever might be more trouble then it's worth. lvl 70 epics, are out even when one dings 70; and finding a guild that will point one in a certain direction, might be out if they're already up to Mags, TK, or beyond.
Worse is, if one isn't aware of these aspects of game, (can't speak for all horde, but at least ali side), some might just laugh and once the rep "oh he's a n00b" is out, well.... Getting some idea ahead of time, and then knowing when to approach whatever guild as one continues their progression can help.
I'll give you some ideas moving ahead. If end game is what you're looking at, this is how I went with my rogue
Perhaps 41 in combat and 13 in assasination would be better, but either way. The 7 in subtlety is soley for the increased sap range. Largely, with end game, people are looking to the rogue for DPS, and combat arguably gives some of the biggest DPS boosts. Sub can be good for PvP, but isn't really centered around PvE raides, and one doesn't tend to see much. As to this char, he lvled combat, but I respeced him at 69 after doing a little research. Lethiality helps with more crit chance on some moves, and anyhow this guy is a dagger rogue.
In practice, when in instances, I was kneck in kneck with an arms warrior for 1st and 2nd place on damage meter, where he had some epics from BGs post 2.3, and this guy's gear (not my main, though current guild has only me as a 70 rogue, and as to my hunter who has run kara for sometime and currently has 7 epics, they don't need another hunter).
Almost any guild, if you're looking at raides, at least ali side will want to know what your kara attunement status is. It isn't impossible to begin this at 68, (though on a rogue it is harder then some classes). Have done it then. Fly (in your case) to stonard, and head to deadwind pass, and take the road south. At the southern most part of the zone, heading along the road, is kara. Grab the 2 quests there.
The water bodies, as you look south, going down the steps left, head straight down. When it opens to a bigger room, take a right, clearing your way in. The loot item you need for the other quest drops off the mobs. Turning right, take that pathway to end where it opens up. On the right hand side, is the well. The other body of water (the lake) is down the other side. This is harder to describe, as the path twists and turns some. There is a point one can see the lake, and jump down. Given rogues aren't best at taking hits, you might need to vanish down there, and find way and complete quest, stealthing back out. Kill however many undead you need to finish other quest.
After turning these in, you need to head to Dalaran. Fly to "Taren Mill"? was it over in hillsbrad, and take road north into alteric, turn left, and go past the Yeti. Head west to the purple dome, but because Dalaran is alliance, watch how close you get. If you go around to the northern side, there is one NPC who is "violet eye" faction and will not be hostile to you. Turn in, get next part, which is to head to shat, and speak to A'dal's apprentice. Just go in there, and you should see where to turn it in.
Now you hit the point you need groups (and will probably end up putting off till 70, unless you have a guild rushign you before. The third frag can not be rushed though, unless you're a druid). First you'll need shadow labs, and the third frag is in a canister off to the side from the final boss. Get a group, get this frag, return to shat.
Now frags 2 and 3 are in the same quest. 2nd frag requires Steam Vaults, and frag 3 requires Arcatraz. Arcatraz requires a flying mount, as there's no lock summon in netherstorm. When you get (if you hadn't) the fp by the summoning stone for tempest keep, you'll see why.
After this (or you can begin before), you'll also need to take a tour of CoT in Tanaris, and open up Durn. Complete the quests there to gain entry to Black Morass. No take the quests for BM, and then just speak with Medivah after you're done, so he can give you a key. Now you take this back to shat, then back to Deadwind Pass, and you're given your kara key.
As to other factions, this attunement will give you enough rep for your CoT heroic key. Getting some others might help your chances, as various guildes might be interested in what your status is on keys, and what heroics you can run. CE is relatively easy, with additional quests in BEM, and if you hadn't done all already, killing naga in zanger can give rep till friendly, and turning in unidentified plant parts till honored (which is now sufficient for the key).
Sha'tar and Lower City, you'll need to run the instances, which will help with gear anyhow. Alternatively, as horde, queueing up AV (which the horde almost wins all the time anyhow post 2.3) will help, and start getting some of the s1. You might want to swap out tier 4 (comparing the rogues) when you get it however; which is a slight different comparison then when I looked at s2 and s3 on my hunter.
In the case of Sha'tar, turning in rep items with either scryers or aldor will give some additional Sha'tar rep
until you hit 5,999 friendly sha'tar. Then you need quests or instances to increase it more. There are some sha'tar repping quests down in bone waist, if you didn't discover already.
If you can go to another guild, working on or having heroic keys, and either have or are in progress (knowing where to go) for kara attunement, and having an idea of builds for raids, PvP, or whatever you're doing; many will look at an application more seriously. Gear, will just have to be built up in time, post 70.
All in all, posting here first is probably best, as on WoW forums some might drill one, and then laugh or take an elitist attitude if one doesn't have an idea, or aren't progressed "to their standards". That progress takes time however, and no one should expect it to be in place pre-70.