If we look at low level Rogue abilities such as: Sinister Strike, Backstab, Ambush, etc. We see a consistent trend of a percentage of Weapon Damage. Damage for these abilities is calculated:
base weapon damage + constant * (attack power)/14
In the case of daggers this constant is 1.7 and other one handed weapons 2.4. This is known as AP normalization. Additionally, only the main hand weapon is used in these calculations. As a result it is ideal to use a slower main hand weapon until you have sufficient attack power to influence your choice.
In the case of Rogues it is common to use Daggers as certain abilities (such as Backstab) require them. At latter levels you will gain other abilities which influence this selection (Combat Swords, Mutilate, Hemorrhage, etc), but at lower levels, slow Main Hand daggers is a preferred choice. A longer discussion of Main Hand weapon choices can be found here.
As a subtlety Rogue your "bread and butter" ability is Hemorrhage which does 110% MH damage (159.5% if its a Dagger as Daggers tend to be faster). I would suggest Initiative + Improve Ambush, making your combat look as follows:
- Ambush (or cheap shot)
- Gouge (later you'll use Kidney shot later in the order).
- Backstab (or Hemorrhage)
- Finishing Move
- Hemo -> Repeat till Gouge/Cheapshot come back up or you have the Combo Points to Finishing move
Garrote can be a good opener if the target stays alive for the full duration. As most mobs won't while leveling, Ambush is usually the better choice.
As a Subtly Rogue you also trade on Dodge, Ap, Crit and Armor pen (the last of which you won't get in bulk till much later). Keep in mind that Agility gives you 3/4, but is not as cost effective as straight AP due to Deadliness.
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If you're not min-maxing at the level cap, your best bet will generally be at least one, if not two, of the three Gathering professions, Skinning, Mining, and Herbalism. If you do decide to take a crafting profession, choose the gathering profession that meshes most closely with it (i.e., if you take Leatherworking, grab Skinning, Engineering, grab Mining, or Alchemy or Inscription, take Herbalism.)
If you want to make money using a crafting profession, the best choice before the cap will be Inscription, as the Glyphs you can produce as early as level 5 will be used even by level 80 characters, providing you with a constant market.
If you want to produce things you yourself will use on a regular basis, Engineering provides fun toys, and trinkets at much lower levels than they'll be availiable as drops. Leatherworking allows you to make your own armor, but drops and quest rewards will, for the most part, be better than what you can craft - at least until the Cataclysm expansion releases. Alchemy will allow you to make a variety of useful consumables, but in general, you will have to make many more than you'll be able to use as you level, and there won't be much of a market for what you craft.
Enchanting is a viable option as well, and you'll be able to enchant your own gear as you level, which is handy.
Realistically, until the +Stat bonuses at 400+ skill come into play, there really isn't a 'best' or 'most useful' profession. There are a few that will be much less useful to you as a hunter, such as Blacksmithing and Tailoring, but for the most part, you should be fine picking out whatever you find fun.
The only other major note worth making is that each of the three gathering professions provides a free 'passive' boost as well. Mining will give you some extra Stamina for free, Skinning will give your character increased critical strike chance, and Herbalism will teach you Lifeblood, a free Heal-Over-Time spell you can cast on yourself on a short cooldown. The crit from Skinning especially should be very handy for a low level hunter, though the other two perks are nothing to sneeze at either.
Best Answer
First, I assume you've read these three threads. To sum it up:
Unfortunately, the best strategy is to plant yourself down and check Sound in Background in the game options. npcscan will play a loud alert when it locates the dragon. So it is best to do something outside of WoW and wait.