guide me , school me... looking at NEWER/NEW 3bd townhomes in the 500k range in North Orange county area ( borderline LA county and san bernadino)

so far i know buy low , keep, fix up, sell higher
-houses at ends of block, near train tracks are bad
-find areas with development going on (commercial, section 8, schools, etc..) or find homes that have been seized, about to be or are forclosed..

can you guys discuss these deeper and also what else is there ?
should i be looking into something in the last stages of being built ?

i want to buy within a FEW months