When testing the viability of a product/service concept, you should aim to get answers to the following:
- Does this concept address a customer need or want
- Are customers excited about the value proposition offered by the product/service
- Is there a business case in this concept
For the first point, you should check with customer is the problem that you are addressing is relevant. Concepts which address real and important problems have a better chance of succeeding.
Once the customer has accepted that they indeed are looking for a solution to the problem you address, then explain your concept and check if they feel that this addresses the problem well and that the price-point at which it does is fine too. You may need to test this with a few customer segments to understand which group has the highest potential for you. Be careful to check that the value proposition and your concept is easy for customers to understand. In many cases, showing them a one-page concept note is closer to how they would see / know about the product in real life. It is unlikely that they would get a chance to hear about the product from someone like you.
After the product is ready, it will be important to get customers to use it to ensure that the product, according to them, delivers on the promise. In concepts that may require repeat purchase, it will be important to test if they purchase it again. There are some interesting ways of doing research on concepts and products, including qualitative techniques and quantitative research.
From a venture creating point of view, it is important to understand if there is a real business case underlying this concept. This will mean working out a fairly detailed business plan, costing the concept right, pricing it right and then seeing if it makes commercial sense to get this product out in the market.