Ok take a couple of deep breaths and systematically look through your house. Check behind things, inside of things, flip over your furniture carefully to see if he somehow got injured and crawled up inside. Look in closets, cupboards, etc until you are sure you have covered all the bases. Don't underestimate him, check every inch of space in your home, use a flashlight and do the check quietly, if he was scared or has been injured, you don't want him to hide from you.
Now, move outside, put a litterpan outside, sprinkle some of the *used* litter around to carry the scent off. The best time to find a cat outside is around 2-3 in the morning. The world is quiet then, and if he has gone to ground and is hiding, he will feel safe enough to come out. Take a half a dozen cans of cat food, go outside, and pop open each one slowly peel them back, run the lid back and forth many times to make as much noise as possible. If you have never fed tinned cat food, use a small box of friskies and rattle it. Sit down on the ground, close your eyes and listen. Relax, reach your mind out and listen for him, shake and open again-
Other things to do is talk to all your neighbors, make flyers, put them up eye level wherever you can. Talk to the mailman, the UPS driver, kids on bikes, anyone on foot. Is he microchipped? Call your vet, and the shelters- though quite honestly, no one turns lost cats over to the shelters anymore, they are to crowded.
Go to Meowhoo.com look under our category of Specialized Pet Services and then Pet Detectives. Sherlock Bones has a really good downloadable e-book about lost pets- I think it is $14.95 but well worth the price! Another thing to do is get a shirt really sweaty with your scent and get it outside into the wind. If you are in a neighborhood where someone would steal the shirt then strip it out, and hang the strips up. You want to direct Morris home. Put food, water and shelter outside for him.
Best of luck, I hope you find him!