You can have the best animations but if the soty is bad, it will have an impact on the final piece.
Some of teh short films I have watched didn't make much sense yet they were well animated, but becausethe story was bad, the temptation to stop watching the whole animation was there.
(Note-Having a good story for an animation is a plus)
-Have a special drawing style can add a plus to an animation like a minus, it could be attractive or 8uninteresting.
(Note: I could create my own drawing style for my animations, but I have to be careful with the way I apply it to my animation).
-Some had a mixture of 3d and 2d objects . Nothing looked out of place, they both blended in well together.
(Note: Mixing 3d and 2d objects could be very tricky, and if in the end they don't blend well together, it will affect the quality of the animation).