1. User experience vision
How do you imagine the product to work? This would be the description and the brief.
2. Identify critical assumptions
Ask for peoples opinions on if you assume correctly, don't whole heatedly trust as not everyone will be truthful; even people close to you as they would not want to harm you with feedback.
3. Make a beta or teaser to validate critical assumptions
There are two types of MVP Concierge and Smoke Screen. Concierge is a manual method which is used to act like an automated method i.e. like the shoe shop. Smoke Screen is marketing without the finished product i.e. making a trailer for a game before it is fully finished, this would usually have a tracked pre-order link or a mailing list to possibly give updates.
4. Release and measure
Target a small audience to see what they think of the product and their behaviour towards it. This is also when the analytics would be collected to judge results.
5. Pivot and persevere
If there are many clicks on the teaser or product but not many purchases then perhaps the product needs to be improved. and after the improvement if there are not many purchases then the idea may not be the best to proceed.