Assuming your best intentions are up against budget (and other) limitations, here's a guide for prioritizing your produce. AKA the "dirty dozen," these are the ones to spring for, organic-wise.
  1. Apples
  2. Peaches/nectarines
  3. Strawberries
  4. Grapes
  5. Celery
  6. Spinach
  7. Sweet bell peppers & hot peppers
  8. Cucumbers
  9. Cherry tomatoes
  10. Snap peas (imported)
  11. Potatoes
  12. Kale & collard greens