If like me, you care about achievements and bought this game without realizing how frankly stupid most of the achievements are then this game is a nightmare. This guide won't make it easy but I can at least give you some pointers.
Additionally since the rules of the item groupings for the achievements seem to be completely arbitrary (some more than others) I think it's important to have a list of all the working items. Since I can only pop the achievement once I can only confirm a maximum of 4 so please comment if you can confirm another item as working for the achievements below.

Update: You can go to C:\Program Files (x86)\Steam\steamapps\common\Wilmot's Warehouse\WilmotPC\img\tiles to see which categories apply to which tiles

One of the most important tools to making it through this game is the config.xml file which can be found in this file path.
Although at first the possibilities in this config seem endless unfortunately 90% of them will break the game when changed so I'll point out the useful ones
productInitialCount - changes the amount of products you start with
productCountToCompleteGame - Determines the total amount of items you can use before the game ends, has gone up to about 500 without immediately crashing, use this if you want to do it the 'legitish' way
"Autoplay" Creates a bot (not borky) to play your character for you, plays very slowly so limiting his stock take time with expert mode is recommended. Frequently breaks especially when settings are changed.

Contained achievements:
Poster #1-8, Clocking out, Dungarees
Posters
Legit
The criteria for getting the poster achievements seems to reach a certain number of products without failing, failing a previous section however will not prevent you from achieving the next poster. You can fail the first 20 @ 28 products and not get the first poster, then play perfectly from 29 to 48 and get the second.
Products required:
Poster #1 - 28
Poster #2 - 48
Poster #3 - 68
Poster #4 - 88
Poster #5 - 108
Poster #6 - 128
Poster #7 - 168
Poster #8 - 188
Cheesy
Simply enter the config.xml file to change the numbers above, or preferably change the initial products to 188, start game play for a few seconds and the achievement will pop.
clocking out
Simply awarded for beating the game, should take about 3 rounds from that 188 starting number if you choose to proceed with that method, it probably pops from starting with 200.
Dungarees
Awarded for buying the last item to be unlocked which is a very expensive cosmetic (96 stars), if you wish to buy everything you must understand the star system. Always serve the customer with the most stars first.
If you wish to do it the easy way the prices of all the items including dungarees can be changed in the xml file.

This is where is gets horrible
To grind all of these achievements normally would take literally thousands of hours, there are 501 items in the game and you can normally only get 200 of these per playthrough.
This doesn't sound too bad but to give you an example I literally didn't see a finch until I did the config method 30 hours in and you need 4 finches at the same time.

So the following method is in my experience the fastest, there are other settings in the config file which would make this faster but they all crash or break the game in my experience.
change neverLoseLives to true for this, so you can do something else as you wait for items to accumulate (optional)
change productInitialCount to 400
change productCountToCompleteGame to 501
change warehouseFullCapacity to 1500
I also recommend playing on expert so you can remove stock takes and make it go faster.

I didn't bother listing a couple of the really easy ones, if someone has trouble with it comment and I'll add them in
Update: You can go to C:\Program Files (x86)\Steam\steamapps\common\Wilmot's Warehouse\WilmotPC\img\tiles to see which categories apply to which tiles

Music



Cryptozooology



Arboretum



Haberdashery



Get in the sea!



Amateur Pharmacist



Pattern Recognition



Time



Insects are my friends



Man's best friend



Sports




Banana Collector




Astronomy




Origin of Species




All the Camels





The English Collection




Quatro Formaggi




Secrets of Wind




Mr. Bricolage