This was the first year in which I actively participated in all the events with the purpose of completing the meta. For this reason, I had to do all the work and it took me a couple of days. I helped myself to Wow.com's nice guide for this event. For that reason, I'm not gonna tell you in detail how you have to complete each achievement, but I will try to give some tips that might help you finish them faster. For the most part you will be ok by just following the linked guide.
- For the cooking quests, you can find all the ingredients in capital cities. No need to buy them from the AH like some people.
- In a similar vein, Small Eggs are drops from low level birds. No need to pay exorbitant prices for them on the AH. Just follow Wowhead's link and see what mob drops them. For Alliance you will have excellent results in Westfall by killing a few of the birds there. You can find similar birds in Loch Modan. If you have extra eggs, DO sell them on the AH for exorbitant prices.
- The Winter Veil Disguise Kit will arrive in your mail 24 hours after you complete Simply Abominable. Don't panic if it seems like it won't arrive. It will, eventually.
- For Simply Abominable you should try to group with other people in the area. It takes a while for the Greench to respawn so this will ensure you don't all wait for ages until it does. Try to make a macro (or just spawn) "/target The Abominable Greench". Hunters can use their tracking set to Humanoid as he's the only humanoid in the area.
- Fa-la-la-la Ogri'la is a bit of a pain if you haven't had any dealings with Ogri'la back in Burning Crusade. You will need to complete a few of their quests in order to get access to Bomb Them Again! The bombing part itself is trivial.
- With a Little Helper from My Friends is another of those holiday achievements that seem to have been put there by Blizzard just to get people to PvP. For someone like me who doesn't PvP it was a bit of a pain in the ass. Here's how I did it. Outside each main city there's a machine which transforms you into a Santa gnome. As Alliance I found the one outside Ironforge very convenient. I then queued up for Alterac Valley since that one always seems to be a frag-fest. Once inside, I tried to get as many kills as I could. Unfortunately that doesn't always work and you do need 50 kills. Once you die, the costume disappears and you have to leave the battle (or wait for it to end) and use the machine again. Like a noob, I didn't know how to leave the battleground so I had to stick it out for 2 complete battles. There simply isn't any button which you can press to "leave the damn battleground". But then I decided to search online and I found the simple way how it is done. Simply type "/afk" in chat and you are out baby! Of course, if you do this, you will be marked Deserter and won't be able to join another battle for 15 minutes. But that's ok.