How can the costs of the US healthcare system be significantly reduced?

There is lots of disagreement about how the US healthcare system should be run. Regardless, the costs are too high. What should be done to reduce costs?

Please be as specific as you can, summarizing your opinions clearly. If you attach links, please have them be to articles of reasonable length or else specify which part of the link you’d like reviewed.

Please don’t just say “tort reform” or “repeal Obamacare” or something like that.