Cata - Glory of the Cataclysm Hero

[Bollwerk]

Feels like it might be about time to get working on this - I'll update as people respond with their own advice and experiences. I haven't yet boxed any heroics, so I'm currently just looking to compile other people's strategies, etc.

UPDATE - Maat has responded with his own personal strategies, broken down by Instance.

Easy

Cataclysm Dungeon Hero - If you can clear the Heroics, then you get this, obviously.

Ready for Raiding - Strafe and use IWT
Rat Pack - This is cumulative - As long as you kill a few rats each time you go, you'll get this eventually.
Prototype Prodigy - Turns out this is quite easy now, with a ranged group and 4.2 gear. You may not even need a healer. Park DPS (and healer) on the top balcony on the far right on the front corner, so they can dps the Reaper as it comes up the ramp. Face your toons in such a way that they can dps the entire 180 degrees left/right in front of them, so that you can ping pong the Reaper back and forth.
It's Frost Damage - Easy if you LOS the Coalesces by using the cabin. Note that you must SURVIVE to get this achievement, but do not need to kill the boss. Maat reported getting knocked into the water and got this while waiting to wipe.
I'm on a Diet - Not too hard if you just circle strafe around him and don't eat bad food. Or eat a good food after a bad one.

Kill It With Fire! - The achievement requires you to kill three soul fragments which have the burning soul debuff. The burning soul debuff is gained when they move over a flame patch left by the phoenixes in phase 1. Just kite the purple bird in such a way that the soul fragments path through the fire, then kill them. Note that you don't have to kill all 3 in one trip. As long as you kill the boss, you'll get credit for only doing 1 or 2 burning souls.

Pardon Denied - Again, with 4.2 gear, this is pretty easy now. If you pop Hero/etc, you should only need to interrupt once.
To the Ground! - With 4.2 gear. this is a joke. Pop Hero/Bloodlust/Time Warp and you can kill the boss before the first wave ever spawns.
Bullet Time - I would guess this is mainly a gear check on your tank and healer. Should be easy in principle with good gear and healing. Maat mentions he had to do 3 waves of ghouls. This may be a cumulative achievement, meaning you can get this over multiple runs. (not verified)

Prince of Tides - Should be relatively easy and mainly just a gear check - Tank/kite the Unyielding Behemoth until phase 3, then kill it. Keep your team close, so when he is doing his cone attack, you can turn it away fast from your team.

Umbrage for Umbriss - CC the Malignant Trogg, burn the boss down to 10-15%, pull the boss next to the Malignant Trogg, kill the Trogg, then kill the boss within 20 seconds.

Too Hot to Handle - Easiest way to do this is to park your dps and healer in one spot, then have your tank drag the boss back and forth through the central pillar every so often (usually when there is 5 sec left on quicksilver armor). If you time it right, you'll get 2-3 stacks each time and hit 15 around the time you kill him. May take a few tries to get the timing down.

Faster Than the Speed of Light - Should be fairly easy now with 4.2 gear - Note that you need about 21 seconds left on the timer when you kill the last elemental (you don't need to kill or engage the boss) to allow time for the role-play to finish.
Straw That Broke the Camel's Back - All you need to do here is strafe/move when Ptah is going to use an ability where you're standing, as his abilities will dismount you.
Sun of a.... - Mainly a DPS check. One option that might help is to pull him far from the center of his room, so it takes him longer to walk back and recharge.

No Static at All - All you need to do is jump at the right time.
Extra Credit Bonus Stage - Extremely easy - There are more than 5 hidden around the zone. Just click on 5 of them to get this.

Rotten to the Core - Pull boss FIRST (from the side), wait for her to land (shield gets removed), then pull the groups and AE them all down at once.

Medium

Vigorous VanCleef Vindicator - Hard DPS and skill check if you do this the legit way. Easier if you cheese it with the warlock or shaman trick (let the worgen kill the people in the 4th part, but have a SS lock or Shaman run to the boss at the end, then rez when you wipe from the worgen killing the first person)

Headed South - Easiest way to do this is to not kill the melee adds as they spawn. Only kill the caster adds. Then when the 3rd melee add spawns, kill it, then kill the first 2 melee adds and then kill the boss. Note that this achievement is PER TOON.
Acrocalypse Now - Difficulty will depend on your choice of tactics and your class and gear. If you chose to just tank all the adds until you have 20, you'll need very good tank gear and possibly 2 healers as well. The other option is to kite the adds with a dps toon like a mage.

Old Faithful - Hex the caster adds, tank the big one to 50%, then kill the small adds one by one. Once the boss is active again, drag the big add to the blue circle that appears on the ground when she's about to do her geyser. May need to pop cooldowns on the tank while doing this.

Don't Need to Break Eggs to Make an Omelet - You can slow the adds, but you can't root or thunderstorm them.

Crushing Bones and Cracking Skulls - Having a pally tank with glyphed Holy Wrath will make this easier. Quake will spawn elementals. Tank needs to collect the elementals, then when the boss gets to 66% you DPS chains of woe, root/stun the elementals near the boss, then the boss does skullcracker. Repeat again at 33%.

Hard

Arrested Development - You will have to make sure you only allow one at a time to evolve and make sure to interrupt both the boss and the Evolved Dragonkin when they each cast Shadow Strike.

Ascendant Descending - You basically just need a class that can slow or root the adds - tank the boss in the middle and kite in a big circle around the outside edge. The difficulty of boxing this will depend on your class makeup.

I Hate That Song - This seems like it would be well nigh impossible to box. The best option I've read about is for the tank to pick up the snakes BEFORE you engage (they don't respawn until killed), dps the boss down, leave the tank and healer up top and run a dps down to each lever. If somehow you can manage to never kill the snakes, you can repeat the process for the 2nd lever pull. But you might need to be really well geared and/or have 2 healers to manage this.