Fool For Love

Firstly I would recommend reading this comment by Bindar. It greatly explains how the Pledge/Gift collections work.

Full list of achievements:

Hearthmender - Use the Unbestowed Friendship Bracelet on 20 players with Heartbroken debuff. You'll find players with the debuff mostly in major city's. Receive the Unbestowed Friendship Bracelet from the [Gift of Adoration: Cityname] or [Pledge of Adoration: Cityname] which might be received when you give an city guard an Love Token. In order to do this you'll need to have either Cologne Bottle or Perfume Bottle buff one you (just right click it). Love Token, Cologne Bottle and Perfume Bottle can be bought from certain innkeepers.

Flirt With Disaster - Obviously, you need to get drunk and have the buff from either Cologne Bottle or Perfume Bottle on you (just right click them). Those are buy able from certain innkeepers during the event. Jeremiah Payson is the c0ckroach vendor sitting on the lowest ring near the bank in Undercity. First throw an Handful of Rose Petals on him (target him and click on the item, he might already got the buff from another player). Those are rewards from the quest: Gift Giving or from any [Gift of Adoration: Cityname] or [Pledge of Adoration: Cityname]. Then /kiss him.

Nearest and Dearest - Complete the quest line starting with Dangerous Love (Horde) or Dangerous Love (Alliance). At the last quest, make sure you click the cauldron!

Nation of Adoration - Obtain Gift of Adoration: Orgrimmar, Gift of Adoration: Thunder Bluff and Gift of Adoration: Undercity. Once received, it should be recorded by the achievement tracker so no need to keep it until you got all 3, you can use it right away for others achievements.

Perma-Peddle - Obtian either Truesilver Shafted Arrow or Peddlefeet (This is the spell found in your pets tab, but included if you already got the pet from last year). The pet can contain in [Gift of Adoration: Cityname] or [Pledge of Adoration: Cityname].

NOTE:

The Perma-Peddle Achievement is no longer a part of the “Fool for Love” meta-achievement.

Link

Be Mine! - The Bag of Candies can be gotten out of any [Gift of Adoration: Cityname] or [Pledge of Adoration: Cityname]. It has 10 charges and its possible to get the same candy more than once.

I Pitied The Fool - Pity the Love Fool on the specified location. Make sure you are on the right spot! Right click the Love Fool to drop a love dummy on the ground. Then just target it and type: /pity. Keep in mind that it agro's surrounding enemies and might be destroyed by them.

Love Fool's can be obtained from any [Gift of Adoration: Cityname] or [Pledge of Adoration: Cityname].

Shafted! - Simply target players and right click the Silver Crafted Arrow. Get this as reward from Gift Giving or any [Gift of Adoration: Cityname] or [Pledge of Adoration: Cityname]. Make sure the players dont have a pet out already, else it wont work!

Lonely? - You'll need to find someone who placed an Romantic Picnic Basket in Dalaran. Those might be received from any [Gift of Adoration: Cityname] or [Pledge of Adoration: Cityname]. Dont just go /sit, but right click the basket and make sure you get the buff Romantic Picnic. You can as well place it yourself, but you still need someone to join you.

(Personal note: If you're on Kor'Gall(EU), look for me. I will be dropping them regularly in Dalaran on either my shaman Phobios or my druid Kapot, since i got them from last year already! =)

The Rocket's Pink Glare - You'll need to shoot 10 Love Rocket's into the air in 20 seconds or less. The thing is you'll at least 2 x [Gift of Adoration: Cityname] or [Pledge of Adoration: Cityname], because you only get them in stacks of 5. Once you got 10, just drag it on an actionbar button and spamclick the button, you'll make it easily.

Looking at the other holiday achievements, barring Brewfest's 1-2 year dedication (Brew of the Month Achievement) requirement, this seems like it'd be the most difficult;
They're making the gifts BoP, you can only get one per hour (if I understand that correctly) and it lasts only 5 days.

Either they need to have the gifts remain alt-farmable or they need to make this title awesome.

"X, Expert Lover"
"Lovemaster X"
"X is Great in Bed"
"X Doesn't Have a Real Valentine, So He Farmed This Title Instead"

Fistful of Love - You'll need to cast (= right click once you targeted someone) Handful of Rose Petals on the listed races / classes. You can get the Handful of Rose Petals from the quest Gift Giving or any [Gift of Adoration: Cityname] or [Pledge of Adoration: Cityname]. Dalaran or any battleground is perfect for this, but may take some time to find them all.

Sweet Tooth - You need to eat the listed sweets.
Buttermilk Delight, Sweet Surprise, Dark Desire and Very Bery Cream can all be obtained from Box of Chocolates which are gotten from the quest Gift Giving or any [Gift of Adoration: Cityname] or [Pledge of Adoration: Cityname].

My Love is Like a Red, Red Rose -
You need to obtain an Bouquet of Red Roses. This item is a drop that occurs during the Valentine's Day event. It drops from:

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• Archivist Galford in Stratholme
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• Illyanna Ravenoak in Dire Maul
• 
  
• Princess Moira Bronzebeard <Princess of Ironforge> in Blackrock Depths
• 
  
• Lorekeeper Polkelt in Scholomance.
• 
  

The first boss in Utgarde Keep, Prince Keleseth drops this now (normal and heroic). Not sure yet about other bosses.
IT DOES NOT DROP FROM ANY OF THE ABOVE LIST ANYMORE.
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In total, this achievement will grant you 130 achievement points, get the title: <Name> The Love Fool and one step closer to the achievement What A Long, Strange Trip It's Been!

Good luck everyone!

Edits:
Be mine now gives 10 points, Perma-Peddle removed from achievement points count-up.