We worked with a consultant to do a Gap Analysis from ISO9001:2008 to an AS9100 "C+"
We're taking the requirements from ISO9001:2015 and As9100 C, but that's all we can do until 20 September when rev D is released. For us, it's been a useful place to start.
I'd suggest grabbing a copy of ISO9001:2015 and start getting familiar with those requirements if you're looking to get a jump.
Good luck!