Keyboard Layout is quite and important thing for any game that requires quick reflexes, such as is in World of Warcraft. In PvE not so much, but in PvP this is quite a different story.
By defualt you'll be using for you primary action bar;
1, 2, 3 (all the way to) 0 - =
You will also be moving with WASD and your mouse. Now this is just a defualt and for true PvPers this layout is a no-no. Why you ask? Because everything in your 12 slot action bar is not right at hand. At times you have to actually lift your hand off WASD and slam the 9 or 0 key, or even further.
This can actually result to clicking and is how people tend to start clicking (which is a bad habit in PvP). Now personally I use the following combo. For my keys instead of having to reach all the way to the '=' key, my furthest away key is '5'. 5 is just as easy to reach as any other key. So how is mine set up? Well, it's the same to many other players and once you master it you'll never turn back. Trust me, it's a great idea to get used to this combo;
E - Move Forward
D - Move Backward
S - Strafe Left
F - Strafe Right
Right Mouse Button (hold down) - Steer
Mouse Wheel Click - Autorun (can be changed to another highly used ability, such as Vanish for Rogues).
The following is what I have on my Mage for my Actionbars:
G - Pyroblast
Q - Fireball
W - WoTF
R - Counterspell
A - Frost Nova
Z - Fireblast
X - Blink
1 - Wand
2 - Frostbolt (Rank 1) - I'm a fire Mage, I use this for slowing targets.
3 - Arcane Explosion
4 - Blast Wave
5 - Autoattack
Off the top of my head that's what I have. This is usally how I open up on a PvE Mob;
G, Q, Z, A, Q, X (if neccessary), Q to finish up (Usually dead before the Blink)
Using this I hardly have to move my hand. This ends up being;
Pyroblast, Fireball, Fireblast, Frost Nova, Fireball, Blink, Fireball
Target is usually dead by the 3rd or sometimes second Fireball.
This is a great keyboard setup and I reccomend it to everyone out there. It actually HELPS to stop clicking, so if your a clicker, I highly reccomend you use this. I know clicking is a bad habit, I used to do it but not anymore thanks to this layout. This is also great for reaction times as you dont have to move your hand anywhere off the keyboard. Also NEVER bind Autoattack to a hotkey. It's a waste of space, use Right Click to auto attack. It saves a spot for something more important. Also casters shouldn't even have autoattack in there action bars at all. Wand people!
If you've got this layout already, good job. If not, make the change today!
Enjoy!