I applied primer to the walls/ceiling yesterday and found some spots that still needs work done to it. How long must I wait for the primer (latex) to dry/cure before applying more joint compound on top? Are there any precautions I need to know of ahead of time?
Depends on the paint, some dry faster then others and it also depends on the temp. and humity.
Wait a day and you would be safe.
Any touch ups will need to be lightly sanded with a sanding sponge and primed again.