The general consensus is that Germany was best to continue Falkenhayn and Groeners' policies, as the Hindenburg Program was a catastrophe, and directly or indirectly caused at least the Coal Crisis, Transportation Crisis, Turnip Winter, and massive labor unrest because of the militarization of factories. They would have still happened, but not as soon as they did. Germany could well have survived until 1919 without starving IMO, but it wouldn't by itself solve the military situation that led to Germany being unable to make a breakthrough.
Here's an
earlier thread on the subject, with a lot of good information, and I made
a challenge with a similar premise a few days ago. It has a slightly different situation, but the idea is the same; run the German war economy as efficiently as possible, and prepare it properly for a long war.
Personally, I was thinking that the best plan in place of the Hindenburg Programme would be to slowly retool the factories, mines, and as much of the German economy as possible, to accept modern (preferably American) mass production methods. This retooling would include assembly line methods (Since Henry Ford invented it just before WWI, I doubt most German factories had a chance to implement them until after the war), a single set of master drawings for all factories to follow (making parts from different factories interchangeable), and research into and use of less resource-intensive production materials and methods. In particular, the use of laquered steel (rather than brass) for cartridge casings and the use of sintered iron or steel for artillery driving bands (rather than copper) could be researched and done in WWI (rather than WWII as in OTL).
At the same time, the production of superior weapons would be implemented while each factory is being retooled anyway. These weapons could come from existing German designs not produced because they would disrupt existing production until now (notably air- and water-cooled variants of the MG14 Parabellum replacing the MG08, MG15, and their variants), or reverse-engineered, developed from, or inspired by Entente weapons with good design features. These would include (but not be limited to) the split trail used by the Cannone da 75/27 Modello 11, the 155 GPF, and the QF 3.7-inch Mountain Howitzer, the simple overall design of the Stokes Mortar (compared to the complex Minenwerfer and Granatenwerfer), and the simple and reliable short-recoil semi-automatic action used by the Meunier rifle. The new weapons would to be modified where possible to simplify production or take advantage of more modern production methods, like using more stamped steel parts instead of machined or forged ones.
Spies would be instructed to attempt to steal industrial secrets in addition to their other duties, in particular from the US, if its relations with Germany aren't bad enough to prevent Germany getting those industrial/production secrets through legal means. For example, once the US entered the war, Ford engineers found a way to increase Liberty engine cylinder production from 151 to over 2,000 a day through new steel cutting and pressing techniques. This and other techniques would be invaluable to any industrialized country in a war.
Any new factories or expansions to existing factories would have to be built with these techniques implemented from the start. While shutdowns for retooling existing factories are staggered to only shut down a few factories at a time, they would implement all of the required modifications at the same time, so that each factory would only have to be shut down once before resuming production at a (presumably) vastly improved rate and efficiency.
A standardized truck (much like the Liberty truck) or, ideally, family of trucks, would have to be designed for mass-production and made for both the civilian and military sectors, as the Army cannot maintain the hodgepodge of converted civilian truck models it has hitherto used for its motorized transport. The same would have to be done with the rolling stock, with the family of standardized locomotives either being designed from scratch for mass production and efficiency(like the post-war Einheitsdampflokomotiven) if resources can be spared, or based on the Prussian locomotive designs (they being the most common type of rolling stock in the rail network). At the same time, a standardized steam tractor should be produced based on some of the components of the locomotives, to free up horses for use in the Army wherever possible on the farms, and possibly to replace some of the gas-consuming trucks in the German civilian economy, where it's not a tactical disadvantage to move slowly and give off huge clouds of smoke from your position. These are one of the few cases where I think that even the existing retooled factories won't be enough to meet demand, so a new factory would have to be built somewhere. The factory would have to be of a considerable size, as not only would it have to replace the worn-out rolling stock in the German rail network, but it would have to produce enough stock to expand the fleet to the size it really needs to be to serve the German war economy.
The rail network itself would also need to be repaired, so rails and railroad ties would need to be mass-produced more efficiently(like almost everything else in the German war economy), perhaps using concrete railroad ties that last longer and are more adaptable to mass production, and ideally someone would find a way to automate the laying or re-laying of worn-out track (much like the way it is done today with specialized machines).
Finally, although it's more a military rather than an economic measure, hopefully someone would have a light bulb moment and realize the Junkers J2 aircraft could fly in bad weather (wood-and-canvas aircraft can't even survive rain that well) and survive impacts from machine guns much better than other aircraft. Hopefully this would be enough to overcome the opposition to its poor rate of climb, and it might prove itself once in service to give Germany complete air supremacy in bad weather by virtue of it being the only aircraft able to fly. If it's possible, the aircraft should be adapted to stamped construction techniques, making it much easier to produce than conventional wooden aircraft.