ahh, if only we had unlimited time to edit posts!

its fine, i get it alot.
its actually really weird that your gecko wouldnt eat crickets, out of ALL of my rhacodactylus, crested geckos eat insects the most readily. uh... i need some information tho.
i find that straight out of the egg, to older adults prefer insects to fruit mash.
how long have you had it?
how old is it?
what was the breeder/place that you got it feeding before you got it?
how many crickets do you offer at a time and how many?
is it eating the baby food on its own? or are you hand feeding it?
if the gecko was on something like CGD, and never offered insects, switch it back to that.
if the gecko was offered insects, and feeding on them well, you can... either try something different [like roaches] or... you can hand feed the gecko, which just means holding the gecko, then hitting it in the face with a cricket untill it tries to bit you and then sticking it in... haha
or... you can get it on the t-rex Crested Gecko Diet. I am not a fan of baby food, because it doesnt have a whole heck of alot of nutritional value, but if it only wants to lick something, instead of hunt, then CGD is the way to go, its a complete diet, no added supplamentation needed, and if you have only one or 2 animals, its cost effective and makes feeding really easy.
i feed fresh fruit so i get the fun of calculating the Ca : P [calcium : phosphorus] ratio! wooo.
ideally you should be putting in 3 or 4 to start.
toss them into the cage, and make sure the cage isnt so big, and with so many hides, that the gecko can find them, if you have things like whole moss in there, the crickets will just climb in and hide.
i just
toss them in, and i will
toss them in directly on top of the gecko, so there is no way he can miss them.
toss them in like... in the evening. right after the lights go out, and they wake up and come out. theyre going to be alot more likely to pay attention then if you are trying to feed a nocturnal animal in the middle of the day.
leave them in over night, dont flash the lights on and try to watch, its just going to distract the gecko, come back the next day, and when you spray the cage, count how many crickets are jumping around, to see weather or not the gecko ate. if there are some left, kill them or take them out.
and always remember to make sure the crickets are apropriately sized... you know, that youre not feeding a hatchling large crickets, or an adult, pinheads

mine... typically eat around 10 crickets a feeding. each. i have also tried an asortment of roaches, and i find they particularly like the lateralis.
i feed 10g and larger animals 4 week old crickets [including adults] and i feed hatchlings to 10g, 2 week old crickets.