Having moved between continents and school districts within them, look for an area with educated and involved parents. Check out the PTA (or whatever the local equivalent is), what fundraising activities are going on to support extra-curricular activities, how willing are the school staff (principle / headmaster) to discuss the integration of your kids into the local system.
If the parents truly support, and are involved with, the schools then the incidence of problems seems to be far less (yeah, I know it never goes away completely) and more time is spent actually educating the kids. This attracts good teachers. With extra fundraising and parental support those good teachers can think of ways to make the syllabus (which is designed to generally turn out good little proles who will blindly consume and obey) into something a lot more interesting. This makes the kids more interested in their education. It's a virtuous circle.
Of course - this does mean finding somewhere where the local populace treat the schools as something more than state provided child care.
This may mean changing jobs, paying more in mortgage/rent, actually spending time with your kids etc etc. We thought it was worth it. YMMV.