Best practices and optimizations tips

Hi everyone, i am and i am new to UE4.

What are the best practices that a newbie SHOULD KNOW, before making any level, model any assets, etc?

at the moment, those are mine:

-Use low poly meshes.
-Each mesh should use 1 single material if possible (to avoid multiple draw calls).
-If you need more of the same mesh (like grass, trees, books in a shelf, etc.), Foliage is the right way.

Please, could you add more best practices/optimization tips that you wished to know when you started UE4?

Thanks and have a nice day!