Nice... everything! You must see these stories pretty clearly in your head before you even put pencil to paper don't you? This will most certainly get Mignola's attention.
I kinda mold the story in thumbnail and rough form. Like for this I started with "Hellboy and Abe ride up to Zeke and then the Ghost Riders appear". So I needed an establishing panel, full shot of the horses (show that I can draw them) closer on HB and Abe (hey I can draw them too!) different angle on the horses, ill toss in a random animal that might say something, and then tease Zeke while showing HB getting down off a horse (again, look what I can draw!).