One thing you need to be very aware of (besides the fact that uncured resin is REALLY BAD for you) is that the release from the film at the bottom of the vat gets trickier the thicker and larger the X and Y axes are of the object. As such you should ALWAYS consider hollowing out your object. The larger the amount of cured resin in the layer the harder it is for the film to release. Is there a rule of thumb? It depends on the printer and the status of the vat floor, but in general if you see a large area that will be cured in one layer hollowing it out is a good idea. How to do that? Meshmixer is good and free.
Another place where prints fail is when the supports are all touching the object at the exact same level and or the layer is way too thick at the top of the supports. What generally happens is the object gets pulled off the supports.