Then you have different ideas, different options. Which one will be the best? When thinking about ideas, you can use tools such as cost-benefit analysis, SWOT or voting tools, pareto, etc. or you can try different ideas to see what happens. Or you can think about the benefits of the different ideas and try to combine them.
As a hobby you can create whatever you want. As a business, you are investing with the idea of a return, so you need to be efficient in the way you spend your time, energy and money.
In "Dragon´s Den" always there is that question or who has used it? What is the feedback from customers? And also there is feedback about the pitch.
In "The Apprentice" there is always one day when they have to do focus groups to receive feedback. There is some observations about how not to do the focus group in www.experiencesolutions.co.uk
Wikipedia provides information about the meaning of focus groups.
It is well known the way "Innocent" tested their business idea with the bins "yes" or "no".
Thinking about ideas can be as easy as listing the pros and the cons. But when thinking about business ideas, business models, products and services, the following video shows very interesting ways to testing them.