This is where the fun happens!

Here are some tips!

Make sure your images reflect your product accurately. You shouldn't use lighting which will hide details of your model.
Check out this free lighting scene to help with any 3D product renders - https://www.imeshh.com/product/product-lighting-scene/
Add as much information about the product as possible, for example, polygon count, image sizes, flavour...? - It feels like much less of a risk from a customers point of view if they can see all the details about the product
Make sure the price is not too high and not too low. Look around to see what similar items are priced at.
Add the correct software. If you create a product for Blender but also export a .FBX, that doesn't mean you should write 3DS as a software option. Yes, 3DS users can import the .FBX, but they will be annoyed that there is no .max file, materials are not set up and units may be wrong. If you just write .FBX it gives 3DS and other software users the choice.
Need any advice? Get in touch! We have been doing this for quite a while now so we will definitely be able to help or give you additional tips if you're unsure!