what paper are you using for your copics?
I find the Aquabee Manga Pad has nice paper that keeps the ink on the surface for longer than thicker papers. then if you work in a circular motion really soaking the paper you can get a nice even coat.
Also for larger areas, you can get the Copic Wide. you can get Empty ones, then buy the refill ink and fill em with whatever colour you need.
you can also paint with the ink, and a sponge brush