One thing I've found that substantially lowers the death rate of my crickets is immediate removal of dead or dying cagemates. Also, the chunky water substitutes (water crystals) are best because the crickets can't drown in them. They'll also die if it gets too cold, so I hung an incandescent bulb next to where I keep their cage. I keep them in a Sterlite container with a handle, it's a pretty decent size but I don't know the specs. I drilled a lot of small holes in the top and sides, and used coarse sandpaper to make the bottom surface easier for them to maneuver on. Rubbermaid containers are good too, taller and narrower is better, it makes it hard for them to jump out.