Info. wherever you can find it.
As a firearms instructor, I've taken courses with every major federal and local agency in the NYC area, as well as with the SIG and S&W academies. There are so many helpful, common sense tidbits that my teachers passed on to me, yet, I don't know of a single printed source where they may be found.
Best thing to do is open yourself to a variety of training sources. I think the best source of combat related skills is with LE firearms instructors. If I started listing everything that might help you win a SD encounter, I'd be here writing the rest of the month and the thread police would ban me from any further writing.
Int'l Assoc. of Law Enforcement Firearms Instructors