Get garlic breath
To get the achievement, you need to pick up a green flame thrower weapon upgrade. It looks just like the regular flame thrower icon but it's green. For me, this pick up spawned at the start of a room on the second floor when I was on a second play through without dying. Just continue on after beating the final boss and you should see in eventually at the start of a new room.
Get the golden bananas
To get this one, you'll need to collect a number of progressively increasing banana bunches in the same room. It will start off as a single banana that randomly spawns, allowing you to tell the difference between it and the regular bananas dropped by enemies. Once you pick it up, a pair of bananas spawn, then a bunch of three etc. Pick them all up in quick succession (I think 6 in total) and the golden bananas will spawn. Pick that up to get this achievement. I got this one in a graveyard so I was able to notice it immediately because the room wasn't filled with enemies or food drops.
Collect 100 treasures
This will take a while but just get all the golden pickup drops you can. Once you get 100 of them or more you get this achievement.
Collect all hint books
This one will take a while. Book drops are rare, so just pick up all books you see. Eventually you will get them all.
That's Your Lot
Reach max level
Very easy to get. Just keep playing and you will keep leveling up.
Collect 1000 coins
Also very easy to get. Keep picking up coins and you will eventually get over a 1000.
Collect 10 golden goblets
Golden goblets are a rare treasure drop from golden chests or random spawns. Whenever you see a golden cup/goblet pick it up.
When Life Gives You Lemons...
I do not know the trigger for this event but rarely when you enter a room, there will be 12 or so lemonade glasses all over the room. Pick them all up and you get this achievement. Just keep playing and you should see them spawn eventually, then rush to get them all.
Collect 100 items in the ledger
Very easy. Whenever you pick up a new item, it will be added to your ledger. Just collect 100 different pick ups and you will get this achievement. Most pick ups are food, and when you play on lower floors you get more food types. That will let you get this rather quickly.
Kill 1000 Frankies
Kill a 1000 Frankenstein monsters, these are the green zombie like enemies that you see in your first room. They are the most common enemy and you will get this achievement quickly.