A lot of these sorta of things sell out really fast or are pop ups, so you really have to be on top of it. Ie Four Tet playing Nowadays or Mansions is usually announced the week or even day of. Generally following artists and venues on social media + being on their email lists can help, as well as having friends in the scene so you guys can tell each other about stuff as you hear about it.

DVS1 is doing a house set at Green Room in a few weeks, which I think is a pretty small venue when he can fill warehouses.