I know about the different ways to tank, however, I am having trouble with tanking as it is totally different to healing.

Healing you just have to stand off a side and press buttons while focusing on unit frames (health bars)

But tanking is totally different! I couldn't concentrate on my positioning, half the time i was concentrating on mangle, lacerate, lacerate when I wasn't even melee range with the mob (spent too much time looking at the cooldown of the skills perhaps)

I could say i wasn't suffering so much when I'm using cat form (perhaps I was using clique hence it was about clicking the frames)

Could any kind souls here please guide me along? any screenshots would be appreciated. I'm looking to build a good way of practicing my flow of tanking.

Sounds like you could use some macros. I need to dive into that area as well. I'd also love to hear some HUD sugestions, in the way of add-ons

But on the low-tech side, I find that it's VERY useful to have your most frequently used attacks on the 1-5 slots of your actionbar (lower left bar). At least if you're using the WASD keys for movement. This way you can just reach right up with your left-hand fingers to trigger the attacks (rather than clicking with the mouse), while using the mouse to control your facing direction and forward movement. Never have to take your eyes off the action. I also just ignore the cooldowns when in the middle of a big fight and just spam the button of the next thing I want to fire. You can still see the global cooldowns fire in your peripheral vision. You end up hearing a lot of "Not enough rage. I need more rage. Not enough rage. etc..." but learn to tune it out (is there some command to stop that? would be lovely)

Just my $0.02

You end up hearing a lot of "Not enough rage. I need more rage. Not enough rage. etc..." but learn to tune it out (is there some command to stop that? would be lovely)Yes. There is a setting the sound section to disable "error speech" or something like that.

I am using the Meta Hud, its quite a good addon imho.

Shortly before I gave up tanking (mostly) for healing (mostly) I set up mouseover macros to help me keep aggro on multiple mobs.

The following is an excerpt from a Wall-O-Text™ I posted my guild forums since I had a couple of people ask me about them.
I was getting tired of tab/swipe/tab/swipe etc etc when I had a group on me in order to keep aggro on them all. (so much easier as a prot pally... Grin ) It was working, but awkward, as when I wanted to get back to the main target, I'd have to either hit tab until it cycled back to the correct target, manually select the target out of the crowd, or try to hit the correct floating health bar. None of them ideal, to my way of thinking.

I had read on a few message boards that folks had good luck with a simple mouseover macro like:

/cast [target=mouseover, harm, nodead] Swipe

but I wanted additional functionality in the macro: If I was not mousing over anything, or an invalid target, I wanted it to land a hit on the main target. That way, I'd never be 'giving up' my main target, so there'd never be a need to reacquire it, and I'd never lose any white hits to a non-primary target.

Why [mouseover] target and not Focus? In the above situation where I'm almost randomly targeting different mobs interspersed with hits on the main target, it trivializes secondary target selection - all I have to do is have the mouse over the intended target when I hit the key. In a situation like someone CCing a single pre-selected target, Focus works better, but what a pain to keep reselecting the Focus target a couple of times a minute to spread the damage around a bit.

This is what I came up with, and it works:

/cast [target=mouseover, harm, nodead] Swipe; Lacerate

Simple, no?

Translated for macro new initiates: if the mob/unitframe the mouse is currently over (target=mouseover) is one I can cast a harmful spell on (harm) and not dead (nodead) then hit the mouseover'd mob with a Swipe. Otherwise( ; ) Lacerate the primary target. As I understand it, a separate target can be specified for each spell in the /cast line. Choices? default to selected target, Focus, Mouseover, LastTarget, and others (much much more info at WowWiki.com)

The instances I tanked using the Swipe mouseover I had several puggers comment on how well I was holding a group of mobs to me.
But now that I've been seduced by the Bark Side of the Force (Resto) I've set up a basic mouseover for each of my heals. My reaction time is so much better... or at least it feels that way to me.

HTH