off the top of my head:
ensure adequate vite d levels.
avoid high phosphorus foods (dairy is on this list and do i have to mention soda? surely we all know by now that phosphoric acid in pop is horrible for our bones)
eat foods that are high in Ca: 24 hour bone broths cooked with an acid to ensure high levels of calcium in the broth, flaxmeal is surprizingly high in Ca, green leafies, fish bones, yadda yadda
take a supplement. if i was depending soley on green leafies you bet i'd also be supplementing
stay alkaline. we know that bodies in an acid state pour off lots of calcium in urine
what else? i dont want to miss anything here...