Use citrus as a frame
Orange, lemon, and grapefruit give a juice a clean border. They keep sweeter ingredients from drifting too far in one direction.
Add green freshness
Spinach, cucumber, celery, and mint soften the sugar load while keeping the drink bright and hydrated.
Keep the finish sharp
Ginger or a small pinch of salt can make the last sip more vivid. It is the difference between a good juice and a memorable one.