How to write good Homestuck dialogue?

I want to write a fanfic but everyone's voices sound the same when I write them, and Homestuck's strong dialogue is a defining trait. I know these characters, I know when they sound right and when they don't, but I can't get the style down myself.

Does anyone have guides for writing specific characters? Like a guide for John or Rose or something. I know they exist for roleplayers and/or fic writers, I've seen the ones on homestuck.net but other than the pages that are literally every line of dialogue a character's ever said, they're kinda bare-bones.