Well, first thing to determine what keybinds you want to use is where your hand-span is, that is to say if you put your pinky on the left ctrl, what number can you reach with your index finger? And what keys do you want to use for movement.
I personally can reach 7 and am kind of locked in to using wasd for forward, strafe left/right and backward. I also have strafe left and right bound to my house (my middle mouse button can be pushed down, left, and right, so down is my push to talk button for vent, and left and right middle mouse are strafe keys).
Now, if you wanna be a baller and try to learn rdfg, it can give you a lot more options because you can reach a lot of keys, but you have to be really good with mouse strafing without using the keyboard at all (aka like the strafe buttons mentioned above) because your pinky and ring fingers will be doing even more key pressing.
While this is a more advanced build, if you're just now learning how to keybind, you might as well get ingrained on rdfg before it's too hard to switch from wasd.
Having said all that, I just kinda grew up on wasd and that's what I'm used to, so here's the general algorithm I have:
1-5 are my main abilities. ` and 6 are HS and Cleave respectively (I'm a prot warrior), and 7 is berzerker rage. So... I really only hit 7 when I really really need to.
next is shift 1-5, these are typically good utility/2 min cooldown buttons, so things like charge, battle shout, demo shout, shattering throw. Things that you'll need to use quickly, but not necessarily often.
Then I start to get into "oh shit" buttons. These are buttons that need to be hit quickly, but are not likely to get fat fingered. I use F1 and F2 for my main cooldowns, so F1 is last stand, F2 is rallying cry. Easy to reach up and just mash those real quick in a pinch. I used to do q for my main tank trinkets, but I actually have hamstring there now, so another utility button. I do actaully hamstring some things on fights (like the oozes on immersius), but if I'm not sometimes I'll swap in some other random fight-specific utility or a racial ability or something.
After this I start filling in more important abilities with the keys around wasd, so q (already mentioned), e, f, c, z, caps lock, etc.
This are important "twitch" keys that I'll need during fights or are supplemental to my rotation. So shockwave is e, execute is shift e, thunderclap is f, raging blow is shift f, commanding shout is z, demo banner is shift z, heroic throw is control e, banner/reck macro is shift d, dstance is shift s, battle stance is shift a, focus target is g, taunt is caps lock.
main rotation abilties: 1-6 or 7ish
supplimental rotation abilities: shift 1-6
utility keys: q,e,a,f,c,z + modifiers
big cooldowns: F1 and F2
I also have a 7 button mouse, so I have things like health stones, heroic leap, interrupts, and intervene bound to my mouse.
The important thing is: don't give up. It's going to be really hard at first to get used to it. Some people even use a mod to make it so that you can't click your bars or even hide your bars to force themselves into the play. Start slowly like just doing some heroic 5 mans or scenarios or something. Once you get the muscle memory down, it help significantly help you become a better tank and think quick on your feet.