Summer Month: 2 
Day 
Interactive meaning the designs can breed (which is the basis of all or most adopts), be entered into shows, be trained, battle, just to name a few. In a way, it is much like Wolfplay, a SIM of a specific specie (although some include a variety of animals).
To make a simple adopt shop
- Find lines: this is optional, since you could draw your own each time, but having a lineart means when you get a lot of orders, you can easily just color in. However, it's a good idea to add credits on your first post or on the actual art where the moderators can easily see.
- Create the concept: what specie is your adopt shop selling? What features does it include? What items can players buy along with the adopt (eg. Gear, decor, mutation boost, etc.)?
- Open: advertise a few times in sales!
Pricing
Usually adopts can sell for 0-50 mush, depending on the quality.
If it's not selling, maybe consider a few points:
Is it too expensive?
Is it cute/cool enough?
Are each adopt nearly identical?
Is your adoptable too complicated?
Are you copying another players' ideas?
please add extras for me! This is only basics, you can see other people's shops, but please as above noted, do not copy and paste .-.