I'm new at this but I'm on my second box of 1000 crickets and I've done a decent job of keeping them alive so far.
The first thing I will say is the crickets definitely need water. If you don't believe me, put a drip of water on the floor of your cricket cage and watch them swarm to drink it up. I've been using water gel from crystals I bought at Lowes (Soil Moist). I also wet down the kale and carrots before giving them to the crickets. I also put some potato in.
This past order was from Ghans and I ordered some of their "Cricket Chow". I can't believe how much of this stuff they eat and they love it. Ghan's says this is the only food they feed their crickets.
So far, my watered and fed crickets seem much happier and much more active than my first order.