Do you have the previous owner's registration? That serves as your title.
You need a bill of sale and previous owner's registration (that says transferable) and that's it!
If there's no registration from the previous owner, you'll have to talk to the dmv about next steps. Technically you should only need a bill of sale and they can do a VIN search, but for some reason they refused to do that on mine so I had to go back to previous owner to obtain the registration.