Hand of Fate 2

This is made easier than it may seem with the correct cards in your deck and knowledge of how the encounters work.

The key encounter cards I used were Helpful Priest, Forgotten Dreams, Temple Prayers, and The Wretched.

The key equipment cards I used were Holy Mace and Gladiator's Visage.

Helpful Priest gives you a card gambit with 1 huge success and 3 success for half your food. A huge success here nets you 2 blessings, the successes net 1. If you want to play it safe, if you do not get a huge success you can immediately press the menu button, select Switch User, and then select your gamer tag and continue your game to have infinite shots at it. This card combined with Forgotten Dreams will net you 4 blessings.

Temple Prayers will get you a blessing for 6 gold, and The Wretched will get you a blessing if you succeed at a wheel gambit (getting either of the 2 food gain cards) and then giving food when asked. Again you can use the switch user trick to repeat this gambit as needed.

Some of these cards are part of the maps themselves, so you will have multiple chances at them.

Each time you go to a new map you will have a card challenge to earn a blessing, you can use the switch user trick to repeat these until success if needed.

The Gladiator's Visage equipment places a blessing somewhere on the map if you complete a combat unharmed. This can only happen once per map, but if you are able to get this item early, that is 3 additional blessings alone.

As for the maps themselves, an important note is that the avalanche card will give a blessing if you complete the battle and then pull them from the snow rather than taking the weapon.

I'm not sure if FAME high enough to use the Holy Mace (14) is required, but I ran this challenge twice, once below that number and once above it. Both times I had a blessing count higher than 12. Neither time did I get this achievement. HOWEVER, when I quit the game and restarted it, it unlocked at the main menu.

The Holy Mace itself has a token that is unlocked by fulfilling the same requirements as this achievement, so it's very possible that the achievement is tied to that token completion.

If it helps, this was the card setup I had:

Encounters
I would say the first three are imperative and the other three are just personal preference. As stated earlier, I'm not positive the fame requirement for the Holy Mace is needed, so take that how you will.
Saint Tala's Day (Platinum, 2 free blessings)
Helpful Priest (1 blessing on success, 2 on great success)
Temple Prayers (1 blessing for 6 gold)
Duel (8 fame on victory, needed to use Holy Mace)
Thomas the Ogre (for equipment gains)
Forgotten Dreams (to replay any of the blessing encounters)

Note that there are also several of the Temple Prayers (2 I think?) cards on the map by default.

Equipment
Aside from the Holy Mace, these were all preference, and really have no impact. The one exception possibly being Gladiators Visage, which can give a blessing (one per map) if you finish a combat without a single hit.
Holy Mace (for obvious reasons)
Gladiators Visage (gives a free blessing on the map after a no-damage combat)
Gambler's Jewel (helps with the Blizzard encounters, if nothing else)
Mask of Holy Fortunes (this one can help with the witch blessings at the start of each new map, by ruling out a failure)
Armour of Gluttony (you should ALWAYS have this. Best Armour IMHO)

Supplies
This one honestly doesn't matter. I always pick some combo of Gold, Food, and a misc item given the mission limit.
+ 10 Gold

EDIT - There are also multiple encounters on the map by default that grant blessings. For "Avalanche," always pick the "Dig Him Out" option for a blessing. And there are two encounters (one after each stage) that have the possibility for a blessing (3/4 chance on the first one, 2/4 chance on the second).