c onverting 2.79 models to 2.8 procedure(s)

Does anyone have a proven procedure for upgrading models from blender 2.79 to 2.8?

I am trying several things like appending or directly opening up in 2.8 and nothing seems work with any consistency except if it is a base model ok, but add particles, rigging, etc and it is all messed up. I used both to do CG Geeks Water Fall 2.79 blend and the rocks combined with trees in the particle system and the smoke simulation was all messed up and linked to the wrong objects....