If you want specifics, I'll go next.
- Make Anakin young, old, Luke's age, whatever, just make his character arc understandable in the context of the entire saga. I would make him a teenager, sans the whiny, but I can definitely see an older Anakin working well.
- More real sets. If possible, make the story smaller than the OT, so that it will dovetail with the originals when they are watched in episodic order.
- Above all: Don't give away the revelations of the OT, like Vader's identity, Yoda, and Leia as Luke's sister. Yes, everyone today knows these revelations, but think in the long term. People will watch the prequels first if they want to see everything in chronological order, so don't ruin the surprise, or step on the toes of the originals.