A good business idea blends your skills and passions to address on unresolved problem
e.g. Passion for walking dogs and start a dog walking business or something related to that.
To come up with an idea, list our your skills and passions, find a problem you can solve and make sure to get feedback from others
Find a market for your idea by entering relate keywords into search engines, tools like Google Trends and social media
A scientist who writes about her daily experiences. Most are drafts but some are publicly shared, like this one you just read.