Put up posters around the area and inform the local animal shelter in case someone finds him and takes him there. My cat dissapeared once but 3 days later came back at 2'o clock in the morning wondering where the welcome home party was.
Rattle his food biscuits, works well with my cat. Also, drag a toy or something around on a bit of string, if he's hiding in a bush or something in a garden, he might chase it and come out.
Ask locals to check their garages and sheds to make sure he hasn't been shut in.
Good luck, try not to worry, and I hope you find him safe and well soon. Remember, cats are very independant and like to make their own rules.