As someone who often has more ideas than time to pursue them all, I've often been asked how I can decide which ideas to pursue at all, and how to validate an idea along the way.
First, I'm of the camp that unpursued ideas are worth zero dollars. (Maybe less than zero, since they are occuyping brain space.)
Like everyone, I have a group of friends who are excellent at "ideating". Whenever we meet for drinks or dinner, we're always coming up with new ideas together, and things that we could improve about every day life.
The first milestone an entrepreneur must hit in purusing an idea is to get talented people to join you in building the idea, and spending consistent notable time working on the idea with you for free. By "for free", I mean no cash, but instead promise of cash and/or equity should the idea become a real company.
If you can't convince a talented person to work with you for free, it indicates one of two problems. Either the idea is not compelling enough, or, you are not compelling enough as a cofounder. :(
If the idea is not compelling enough for people to put in real hours for free, the idea is not worth pursuing.
To be a compelling cofounder yourself, you need a track record of success. Not building billion dollar companies, but instead, just showing you can get things completed, things your friends would be proud of. It is this demonstration of ability to complete things that will help convince your friends that your new idea will get done as well.