Camping Idiot's Guide to Orange County?

I am located in central Orange County, CA, and I'm trying to get into camping. When I was a child, My family used to go all the time and I would start going again, my problem is finding a camping / making reservations. How does this work in general? Are reservations usually necessary? Is there a good online source for camping (it seems that Google only produces lots of ads)? Are there books in the library anyone can recommend? What about real campsites can recommend (if Thanks species in the southern CA)?.

look reserveamerica.com

Beach Camping in Humboldt County