Find a popular service (Salesforce, Wufoo, Asana, Xero, Gmail, etc) and scour the forums for things people repeatedly request to be added. Pick a popular reques

Find a popular service (Salesforce, Wufoo, Asana, Xero, Gmail, etc) and scour the forums for things people repeatedly request to be added. Pick a popular request that you have reason to believe won’t be added as a feature soon (e.g. company said so, it’s been years of waiting, it’s outside of obvious product expansion, etc). Go build it as an add-on (chrome extension, api, etc). Market it on the forums. You can even reach out to people and ask in advance if they would pay. Show them screenshot mockups and state a price.