reasearching and screening GCs

[Ki Lee]

Newbie flip investor here.

I would like any advice on how to research, screen, and interview GCs for rehab projects.  I was told to do background checks, but obviously only for 3 or 4 that I narrow it down to.  Besides referrals, Thumbtack or Angie's list reviews, what can I do to find a superstar contractor?  What research can I do online?  what questions should I ask?  Any terms that I need to clarify on the initial conversation?  I will have a property under contract soon(seller countered and we will most likely accept the counter) and now there is this massive pressure to find a hire a great GC.  Any help will be greatly appreciated!