Tips before open-sourcing a project?

I'm getting ready to open source a 2+ year project (a calendar app). I'm trying to make things attractive for potential contributors, so I'm: - creating a docs site and cleaning up the code. - letting devs in the niche know via direct outreach - considering doing a quick & minimal launch here on Product Hunt Anything else I could be doing to increase the odds of devs finding and using the code?