Controls in World of Warcraft
You will perform much better if you customize the default controls in World of Warcraft. It is one of the simpler things that you can do to improve, though it will feel a bit uncomfortable while you retrain your muscle memory. Stick with it! You won't regret it.
The best way to move your character is use W, A, S, and D in combination with the mouse. The default key bindings are not set up properly for this. The first thing that you should do if you haven't already, is bind Strafe Left to "A" and Strafe Right to "D". You will never need a key for Turn Left and Turn Right -- don't even bother rebinding them.
With that done, you can now use W to move forward, and A and D to move left/right without turning your character. (You can backpedal with S, but you move more slowly so keep that in mind... it is often better to turn and run.) To turn your character, hold the right mouse button and move your mouse. That's it! If you have been using the keyboard to turn, this might feel awkward. Just fight through it, you will perform much better if you do.
You can hold the left mouse button and move the mouse to change the direction you are looking. We would recommend that you go into Interface, Camera, Camera Follow Style, and set it to Never adjust camera. That way the game won't move the camera around on you. It's better that you get in the habit of controlling it yourself.
A useful tip if you control this way: say you are facing a boss and shooting at it, but you use the left mouse button to look behind you. You can quickly turn around and start moving that direction by pressing both mouse buttons.
Spells and Abilities
Now that you are using W, A, S, and D to move your character, you want to bind your spells and abilities to the keys closest to your fingers. Anything that you use often or that you might use while moving should be given the best keys. Things used infrequently or usually when standing still can go on the less comfortable keys.
When controlling in this manner, your left pinky will naturally rest on the left shift key, giving you easy access to a lot more bindings. For example, "E" and "shift + E" can be used for two different spells.
Below are recommendations for the best keys to use for your spells and abilities. Keys in green are generally easy for most people to use while moving. Keys in yellow are decent but a bit more of a stretch. Every keyboard is slightly different in dimensions and key position, so feel free to customize.
If you have a mouse with convenient and comfortable extra buttons, those are also good for binding abilities.