Open source projects are mostly distributed undertakings of a virtual group. That makes it even more important to care about giving them some sort of a home which gives people a way to connect and where they feel safe and taken care of.
The following stepping stones form the path of home. They are not in a specific order. Each project will pick and arrange them in a way that is suitable to them.
Things which can give a virtual community an identity: Home page, trademark, logo, mascot, ... Treat it as a visible sign of your home.
While virtual collaboration in a distributed way can be very effective and has a number of benefits, direct human interaction in person has a quality which can't be replicated virtually. Physical meetings require extra effort and might not be always possible. Use them as catalysts where you can to infuse energy, inspire action, create bonds which last long beyond the meeting itself.
In many ways the code repository is the de facto home of a lot of what is happening in the project. Treat is as such, with care and love. Make it welcoming for the inhabitants and your guests.
Software is about people. Creating software is a social activity. It sometimes can be tough to do this in a distributed way, publicly, on the Internet. Conflicts happen. Burnout happens. But you can do something about it. Take care of your people. Protect your people from abuse. Be kind.
What is the tone in your community? What are the values? Is it inclusive? Do people take care of each other? Are they having fun? Is the community welcoming, humble, supportive, respectful?