Well as far as Collared egg clutches go the reading that I have done on them, that are notoriously hard clutch to hatch. In my case though a combination of not properly brumating them and being their first clutch more than likely caused their failure.
With Thelma's first clutch I didn't have a hovabater so I set up something as best as I could. I had managed to grab her eggs before they did dry out.
Bonnie's clutch I had the hovabater up and running all was right with the setup including the dampness levels of the vermiculite.
From all my reading with books and here on the boards, the keys to a successful hatching are:
1. proper brumation
2. proper temperature in the hovabater
3. proper dampness levels in the vermiculite.
Collared the biggest thing to do is look at this as a time to learn don't beat yourself up if they don't succeed.