Full disclosure: I am a raving altoholic. Group sessions and focus exercises and shiny, shiny purples have all failed to keep me away from that Create Character button. As a result, I've levelled a lot, and I'm good at levelling quickly and efficiently.
I suspect most people know that the best way to level fast is through optimised quest circuits. Hell, Blizzard seem to have cottoned on to that: compare the compact quest hubs we have now to the sprawling mess of objectives and travel time that made classic levelling such a time sink and you'll see what I mean.
These days most quests run together; you finish them all in the same general area; moving from target to target happens naturally; and creating an optimised circuit is mostly just a matter of making sure you pick up all the quests and take note of any quest starter items you find. But it is still important to plan just a little if you want to to push your speed to maximum.
That wider issue - moving between different quest areas effectively - is mirrored small-scale in basic movement between each of those scattered tablets you need to loot, or those mobs you need to kill. If you want to level really bloody fast, you will be doing two things: you will be looking for the next target as you're dispatching or looting the current one, and you will make sure you cover the ground between here and there as swiftly as possible.
With that in mind, there is one thing I hate above all others. The peripheral mob.
The peripheral mob is a dick, and don't let it argue otherwise. This sucker is out of range of your usual pulling skills: your spells, your taunt, your bow. It's sufficiently far that you're going to have to run a bit to get there. But it's actually a pretty big bit to run, you know, I mean, should that really be taken on foot, or is it worth mounting up to get there? Is it worth mounting up to get there? There's a 1.5 second cast time on my mount, will the speed of the mount make up for that pause while I summon it? Would I have pegged it into range by then if I'd gone in on foot? Will I be shedding precious seconds if I do, or if I don't?
By this time I have wasted precious seconds on mental contortions, of course. If I'm feeling particularly twitchy, I may have busted out some maths.
This is one of the reasons I adore the monk class. Roll is sufficient to bypass this whole problem. If you find yourself surrounded by peripheral mobs, all loitering at the kind of distance that suggests they all hate their neighbours, there's no need for tears or calculators. You roll. Maybe you roll twice. If you've specced into Celerity, maybe you roll three times. If you've specced into Momentum, you're practically sprinting. And if you're a windwalker monk, you fly across the questing zone and kick that peripheral mob in the face.
It's very satisfying. Not just because of the face-kick, no: because the cooldown timers on roll and flying serpent kick are such that one or both will be done ticking down when you finish killing and looting, but not so fast that there's the niggling feeling that you're wasting potential rolls.
And yes, alright, both skills are probably tuned for PvP and the PvE endgame, not ridiculous people like me with my, er, eccentricities. Still, when a class has such tools as Enlightenment to boost them through the world, I have to wonder if it's all a big conspiracy to make monks especially addictive to level. I can only approve.