1) The External World is Key to the Comedy: Great comedy often comes from the conflicts between a weird thing and a normal thing. So in WHAT WE DO, you've got a bunch of vampires (weird) living in Staten Island (normal). Brainstorm some normal-life kinds of situations--Malls! City council meetings! Christmas carollers!; or vampire-kinds of stuff--Problems with Silver! Always hungry! Can turn into bats! And see how they can interact.
2) They Explore the Space: Once you've set up your premise and characters, take the time to explore their implications. We know that these are goofy/clueless vampires who really just want to hang around. So what else might be true about them?
3) And Use All their Toys: Where most mockumentary-type shows ignore one key element of their series, the documentary crew, WHAT WE DO has repeatedly gone back to them in different ways as both objects of incidental harm and occasional embarrassed (aka "Whoops, sorry about killing your guy") kinds of conversation. They're not main characters by any means, but they are part of the fabric of the show. So what might be the next ways to use them?
4) Guillermo Wants Something (Outrageous): Stories live and die on the desires of their characters. Desires create paths, possible conflicts and choices. The bigger or even more absurd the desire, the bigger the choices and obstacles involved. On WHAT WE DO, Guillermo wants to be a vampire, and that desire leads to both hilarious conflicts, as the vampires show no interest in siring him, and ever-stronger choices, as he ends up having to protect his vampires from the bigger world.
5) There's a Big Picture: From the pilot WHAT WE DO establishes a bigger world to the story, the Vampire Council, and their desire to rule. And over the course of the first season our vampires fall afoul of them, courtesy mostly of Guillermo, who comes to discover he is a Van Helsing, setting up a fresh new take on the Dracula story. And knowing the big picture is that tale, what other elements can we draw out or bring in? For instance, what about introducing a Lucy figure that Guillermo falls for? Or a Renfield who is like Guillermo's equal and opposite? Or what about pitting Guillermo against his own vampires?
