To do that you need to get out of the proverbial building and find people who you think might have the problem and ask them some specific questions that will help you identify whether there is an potential or not.
I reccomend reading "Running Lean" by Ash Maurya as it provides a great framework and sequence of steps to follow to validate your idea
In terms of the kinds of questions you might ask: A. Customer Segments: Who has the pain? • How to identify early-adopters? Ask some introductory questions to collect basic demographics that you believe will drive how you segment and qualify your early adopters.
B. Problem: What are you solving? List (up to) the top 3 problem you believe you are solving • How does the interviewee rank the top 3 problems? • What is their pain level for all of these problems: must-have, nice-to-have, don’t-need? • How do customers solve these problems today? – This is generally the heart of the interview as they do a lot of talking and you ask follow up questions based on their responses.
You are done when you have interviewed at least 10 people and • can identify the demographics of an early adopter, • have a must-have problem and • can describe how customers solve this problem today
Hope that helps.
There's a dozen new ones so far this year. Maybe two of them have any potential for market validation (I'm evaluating one of them right now). The rest are almost certainly projects where, as neat as they would be, there's probably zero chance anyone would pay to solve that problem.
I'm not entirely an idealist, so I recognize that we need a balance between focusing on ideas that make us money, ideas that are just for fun, and ideas that might make the world a better place. But in the end, I want to be one of those old people who looks back happily on a life filled with meaningful work.
So to answer your question more directly, I choose to focus on ideas and projects that maintain a balance between earning money, playing with fun ideas, and making the world a beter place.
2: I discard those that don't resonate with anybody else.
3: I then look for excitement and eagerness from discerning readers.
4: Then I start with whichever I'm most excited about, of those ideas.
I've never been in a situation where there's more than one idea at this point, but if there is, I'd focus on whichever I could execute faster.