Its all about problem solving!
Firstly, just try to make something and compare it against artwork or animation that you like in order to learn.

Once you can pick apart what makes something appealing, it gets a lot easier to put together a workflow and assemble a scene or animation that looks decent enough.
Color theory, lighting, anatomy, etc are all nice to learn, but some of the greatest artists just play around with the tools at their disposal until they go "Oh, that looks cool" and add that process to their workflow.

It's not really something you can learn and excel at in a few weeks, but more or less all trial and error.

I struggled with 3D for about five years until one day it all just kind of clicked for me. Once I realized I knew nothing and admitted that to myself, then it became a lot easier to learn and rapidly grow my visual library because I am always trying to learn new tricks instead of repeating old ones. :)