Glad handing goes a long way.
Be sure EVERYONE (PCPs, surgeons, the ED docs, hospitalists) in the area has your cell number and knows that you're happy to help out at any time. It's way easier to text "hey, got a second for a quick question about X?" than it is to look up who's on call for hem/onc, call the office, get put on hold, get told that person's in a room, leave a message and get a call back.
And all those BS consults that
@NewYorkDoctors mentioned are a great way to not just bulk up your practice with chip shots, but also to get the "good stuff" from those same referring docs when the time comes.