How can cities like San Francisco solve their homeless problem?

I hear a lot of talk about homelessness but it seems to mostly consist of acknowledging that it’s a problem and declaring that something needs to be done about it. What actually needs to be done I’m less clear on. What are your solutions to homelessness? What role does mental health care play in combating homelessness?

This question doesn’t have to just be about San Francisco, but I use it as an example because SF has a notoriously bad problem with homelessness, worse than most U.S. cities (San Jose too) and I used to live in the Bay Area so I’m familiar with it and its incredibly high cost of living.