Door knocking with fliers is best way to find. (By doing so, I've located mine missing for 2.5 months. The posted signs help too.)
Chipped? Notify of lost status and confirm info is utd on manufacturer's website and found.org (now my24pet.com).
Use a camera so you know when he is coming around. Ask neighbors to check their cameras. Create a scent trail with dirty clothes.
I often lock the ones inside up and sleep by a cracked door with the hopes that the missing one will sneak in for food so I can close the door on them. Using a camera helps.
Consider using an animal communicator.
Do check ALL area shelters' websites daily or, better yet, go there every other day. (Google animal shelter.)
For what to do and where to do it, see: https://m.facebook.com/story.php?story_fbid=3453873658047583&id=100002749496752
And/or Nextdoor.com groups: the pet posts in the Tucson (Pet) Resources Lists for places that can help. [Your picture, drop down to your groups, See all, Search bar: List]
Cats are usually found within a four or five house radius. They may be hunkered it down, hiding or trapped somewhere. Ask your neighbors.
Go outside at dusk or dawn, with a flashlight and look for your cats eyes reflection. Shake a container reprice to get his attention. Cats may not vocalize so you must search carefully.
Make an online report with
lost.petcolove.org which posts to the PACC website using facial recognition.
Make an online report with the Humane Society.
Check on the PACC website under cats that have been found.
Go to PACC in person every day to check.