This is my first year breeding and I'm using eco earth with great success.

The trickiest thing imo is getting humidity right, too wet or too dry will kill eggs. With eco earth you want it to be moist enough to clump up when to squeeze it but not to be able to squeeze water out. (at least thats how I do it)

I like temps to be 75-78*F. From 72-80*F is the temp range many people incubate in

Also what are you feeding the geckos?

If this is the females first season you are a lot more likely to get infertile eggs, eggs that just die, or eggs that simply never hatch.