Put a sign in the yard, advertise on Craigslist as was said, or other websites, and word of mouth. I don't see much return when I advertised in the SacBee. However, be very careful on some of the websites for scams...such as someone saying they want to rent it from out of town, they're sending you a check via Fedex for more than is owed and they want you to pay the difference into one of their accounts....there's more like that but it's too long of subject to post here.
My one advice I ALWAYS follow....I hold my second visit with them in their current residence. That's where I bring the paperwork. Everyone says they're clean, etc. etc. but seeing is believing. REst assured your property will be in the same condition as this house they're currently living in.
Also, make sure you know tenancy laws in California...how much you can take for a downpayment, terms of a lease vs. a month to month contract....it's not as simple as you might think. In fact, if you've never done it before, either enroll in Rental Housing Association and learn it yourself, or hire someone like Ed Favinger to be your property manager.