Startup can be very counterintuitive. It is like skiing. The list of counterintuitive for startup:
Growing fast. Make something that user really love.
Startup are consuming. You can't have vacation because things happens... You have to deal with it. You can only learn how to start a startup by doing it. Success can take away your serendipity.
If you unsure whether you can do it or not, you need to try it.
Success startup always started as side project.
How to work on a good side project:
You don't have to be technology in startup.
Live in the future. Know something that ought to be exist. For example, a person just want to talk to his girlfriend through internet. So he developed a software that send sound package through internet.
General interests and curiosity would be your foundations.