First, I'm not sure how I would search for this topic so I thought I'd just post and see what advice I could get.
What I'm interested in learning about is specific to tanking one large mob with a frontal cone/cleave and possibly a tail swipe. As a healer, I've raided lots and lots and there has been quite a lot of bitter mention of moving the boss wrong and getting half the dps breathed on, etc.
I've kept this issue in mind while tanking, and I've been constantly trying to position mobs in certain ways. At first I just did this for fun, but I learned about the importance of frontal positioning for shield block and so that's always a good reason to have a group positioned well.
However now that I'm entering into the Wotlk pre-raiding stretch I really need to perfect this movment thing. I've been noticing that mobs really like to stick to my side or wiggle around - facing the dps and then turning back to me - when I move.
At this point it's frustrating enough that I've started to move with a serious conviction right through crowds before turning around and hoping everything stays in a cone in front of me. All my small movements seem at best luck-based and at worst disastrous..
What are the tricks for movment and positioning? Are there any video demonstrations solving problems like mine?
Welcome to the world of "fixed" bugged mob pathing. The issue was way worse, the "fix" has lessened it somewhat but it's still there.
From what i can see, the problem arises due to server lag. You position a certain way, a few seconds later thanks to lag, the server interprets your location to be someplace else and repositions mob relatively. Initially the bugged version had them actively trying to get to your back. Now they dont but they still wiggle. Practice will get you to adapt to the way mobs move and start positioning them properly.
Otherwise, as a general way, you want to position mobs facing their back to the raid (or if it has a tailswipe, their side). This minimizes the raids runtime and dps dps better from behind.
One other thing i do is i ALWAYS move/turn the bosses the same way. My raid knows that when i pull Onyxia / Marrowgarr/ etc, i'm going to pivot him from the right side, therefore everybody knows how to avoid the tailswipe or getting into the frontal cleave. I dont need to spell it out every time, they know implicitly.
One more help in positioning & movement would be to move faster than the mobs. Which means if you're kiting them, or dragging them to your tanking position, you'll need to be moving AND keeping your back away from them. The way to do this is strafing. If you backpedal, you'll move slower than the mobs and they'll end up all around you. If you strafe, you run at normal run speed, your side is considered your front, therefore benefits from shieldblock, dodge/parry/etc, and when you get to your destination, the server will have the mobs walk up to you meaning they position themselves.
I also suggest watching Ciderhelm's advanced pulling videoguide as that also has some good movement tips in there.
Ciderhelm's Tanking References: Position and Movement can be found here. It is excellent. I'm actually putting a post together for my guild forums about how I applied the ideas and how I practiced the techniques.