I'm at the Imagine Cup Finals, and I'm getting to see lots of students' projects, and lots of ideas. For competitions like that, there are of course a set of objectives that are slated as part of the competition -- work toward those goals and do better than everyone else. Sure, the Imagine Cup's goals are broad -- "Make the world a better place" -- but they're still a set of "mission objectives."
Real life does not have such easy, slated goals.
Let's say I wanted to start a startup tomorrow, with several ideas. How would I choose between them for general applicability to the masses?
(There's lots out there on how to take an idea and sell it, but I'm trying to choose the idea based on sell-ability)
Answer these questions.
"Let's say I wanted to start a startup tomorrow, with several ideas. How would I choose between them for general applicability to the masses?"
Well why is that the criteria... applicability to the masses?
Would you rather try an idea that everyone alive might want (Pet Rock!) that has a 10% chance of success or a niche idea that few would want that has a 90% chance to become real?
I'll take the niche...you can make a hundred of them.
From the context of your startup I would say the best of your ideas would be the one you think you could follow through on without stalling. If you don't believe in your idea enough to think you can follow through on it from the beginning it probably isn't the best idea, for you to execute.
On the other hand if you a merely judging if an idea is good in general I find it very hard to figure that out on your own. You will definitely need to get reactions from other people to feel out if your idea is extremely good.