How old are they Katie? If they are babies they should be eating just about every day. You can try small mealworms in a dish with a little calcium, but will probably have better luck with some 1/4-1/2 inch crickets dusted in a calcium supplement. The crickets should NOT be bigger than the geckos head or they can choke. Offer like 5 at a time and if they eat them all give them a couple more. You've given them too much if the crickets remain in the cage and the gecko is done "hunting". Remove any remaining crickets as they will eat the geckos poop and infect the gecko if eaten after that. Hopefully you are keeping the geckos separate so you can tell who is eating as who is not.