For mediums, lead for sketching or white pencil (the name of the instrument always escapes me) and oil for painting (on panel and or canvas.) He also uses photoshop for certain paintings (if you would like to consider that as a medium.)

As for techniques, I’m not precisely sure what techniques he uses. He’s brushstrokes are simple though. If you’ve watch any of his painting videos, you’ll see that most of paintings are layers of paint over layers of paint and a lot of shading and shadowing to convey depth and moodiness.

All his paintings follow a certain color scheme and solely are connected by the palette he uses. Each painting might be different with a different story behind it, but are connected through the colors he uses in each set of pieces. 

This is purely observational, if anyone would like to make an input, please do.  :)