If it were completely clear as to how this could be accomplished, it is likely that we would already have accomplished it. Therefore, it must be hard to understand for certain how to cut these costs. It appears that there are two possible approaches to reducing costs. One is to promote competition while the other is to centralize control over the health care system in the hands of the government.
Liberals typically believe that the way to control costs is to have the government control the health care system. They believe that we could control costs by cutting out the profits that hospitals and other providers take. They believe that we could control costs because the government, as the dominant (or only) buyer of things like drugs could demand better prices from the drug companies. In these ways and others, government control would reduce costs.
Conservatives typically believe that only increased competition can control costs. They believe that there should be, for example, more insurance companies competing for customers. They believe that this (along with reforms to make consumers actually aware of how much their health care costs), will cause insurance companies to provide insurance at the lowest possible price. This would give the insurance firms an incentive to pressure the health care industry for lower prices.
There are, of course, people whose ideas are a mix of these, but these are the two main types of approaches being proposed to reduce the cost of health care in the US today.