What type of litter do you use? If you use clumping, scooping a couple of times a day works. I scoop a minimum of 3x a day (for one cat) and rarely have any problems with odor.
If it's non-clumping litter, you'll need to scoop out the solid waste every day and change the litter completely every week.
Keeping the litter a minimum of 3 inches deep also helps.
I use the Arm and Hammer Clump and Seal litter. Its a little more expensive though. I have three cats and I'm a fanatic about keeping the box clean. I'd clean in the morning before I go to work, and later when I came home or before going to bed. Invariably, I'd come home from work and one of the cats had just done their business, I'd walk into the house and there would be a wall of stink!!!
I've tried different litters. The clump and seal's claim to fame is if the "stuff" stayed in the box it would be odor free for 7 days. Of course I wouldn't wait that long, I still clean the boxes twice a day. It sure does stop the stank before I get a chance to clean the boxes. I buy two boxes at a time at wally world.
l'm going to change it up a little and say that THE biggest thing to eliminate poop odour for me (the cats!) was switching to a raw diet. They can poop in the smallest bathroom while l'm in there with them and there is no smell. One of the biggest upsides to the diet switch for sure.
The best way is to scoop the litter on a daily basis - I scoop 2-3 times or more if needed. Perfumed litters smell worst than the presents your cat leaves you and can stop the cat from using the box altogether because they are very sensitive to odors. Dr. Elsey's Precious Cat Litter is a hard clumping litter, no scent and very little dust. But if you don't scoop on a regular basis you will have odor - won't make any difference what type of litterbox or litter you use, if you don't scoop it will stink.
Scooping is a fact of life with cats - no way around it. A clean litter box is the key to an odorless litter box. Think of it this way, how much do you love using a Porta-Potty ... exactly ... that is the human version of an unscooped cat litter box.
The best advice I know was given by DVM Lisa A. Pierson at catinfo.org "Litterbox from your cat's point of view". Basically, it's clumping litter 10 cm/4" deep, clean it two times a day, if wall become polluted - clean it thoroughly.
Raw or half-raw homemade diet should help too. I'm trying to intoduce my cat to it, but it is too early to tell.
For storing poo that was removed from litterbox I use LitterLock, to collect and store all until garbage removal day. Keeping LitterLock outside (balcony, porch) even better. Keeping litter box in the room where window can be open for ventilation was indispensable for in my experience.
If it helps, 3 cats I know were fed in shelters by dry food (dry Scientific Diet Adult formula), at the time of arriving home had smell-less poo. After switching to the wet food, very strong obnoxious smell appeared. No matter, was it low end (Friskas pate), or higher end food (Weruva, Merrik, BFF, Nature Calling). 3 different breeads of cats, healthy, same result.
Before going this way, you may want to read about wet food beiong better for cat's health, here on forums or at CatInfo, feline nutrition.
Good canned food no smell. Fresh step Extreme scoop twice a day. Also give vet's best hairball relief digestive aid it is all natural tab cats eat like treat (amazon.com) it is inexpensive and helps with hair balls and digestion and constipation