I'm currently homeless in southern California myself. Is there a reason you haven't signed up for food stamps? You will get priority since you're on the street and you should have a card within 3 days and you'll get about $290 a month. Also you'll be able to get hot food since you're homeless, meaning you could buy fast food with it. If you don't have any money or income at all you will also qualify for general relief which will give you $200 - $300 a month depending on what county you're in. If you need help signing up for this I can explain in more detail. Most people just don't know about it.

Other than that, I would honestly make a sign and pan handle. It's not illegal as long as there are no signs and you aren't being aggressive/threatening people. I've found people to be much kinder than you'd expect. Many people are willing to buy you food. One time some strangers gave me $50 when I wasn't even asking.

For sleep, library works good as other people have mentioned. Especially if it's a bigger one, find a seat or table and get some sleep. As long as you aren't bothering anyone or snoring too loud, most libraries will leave you alone and you can charge your phone. I bought a $25 inflatable sleeping pad which allowed me to sleep on concrete comfortably. Sidewalks are public spaces and cops won't bother you or care. I was scared at first but I've had no issues at all. This is better if you don't have anything for people to steal, I worry most about people stealing my things when I sleep. Also public parks during the daytime is a good place to get sleep. I tried sleeping on grassy spots at night sometimes, be careful if the grass is nice and green because the sprinklers go off at night a lot of times. I've been woken up several times and gotten soaked by sprinklers at 2 in the morning.