As said elsewhere:

I would like too try this one.

First, lets define the problem into different areas as follows:

Politically-Diplomatically-Industrially-Militarily.

Politically, the German Industrial and Military assets ended up being controlled by Nazi officials who didn't do a bang up job making effective use of these critical elements of German war-making potential. Better planing and management could have gone a long way. Hitler was an Army man, and even there Germany had many shortfalls. The Air force and Navy got even worse controllers.

Diplomatically, maneuvering into a war with both Briton and France {simultaneously} was going to be unavoidable (IMO). This being the case, the need to find a way too avoid fighting the US and USSR is critical. Germany cannot fight and defeat both Briton and France, while America and Soviet Union are also enemies.

Industrially, If you accept that Germany MUST invade, conquer, and occupy both Briton and France, then German Industry must build the ships and planes to make an invasion of Briton feasible. Unless Briton is conquered, German Imperial ambitions cannot be made safe.

Militarily, you cannot read any dozen books on WWII and not see many things that could have been done better. Not just actual tactical fighting of battles, but strategic planning and Grand Strategic weapons buildup/design. If Germany is going to make a war upon the USSR, then they must first secure control of the eastern Atlantic to prevent American aid to USSR (to say nothing about invasion), and to do this the UK must be solidly in German hands.

Another area I believe the Nazi's were sadly lacking in is the full exploitation of conquered nations. Their Territory, Populations, Industry, and not just their Resources. I think that some careful thought ought to have been given {prewar} to this area and extensive exercises run to gain practical knowledge on how to re-locate conquered civilian populations, how to go about drafting 90% of a conquered peoples able-bodied males into your Infantry and Forced Labor battalions, and how too replace male factory workers with women.

What I hope for in this thread:
Posts that contribute too the debate.
Posts that identify which area(s) the poster is addressing.
Posts that {collectively} thoughtfully and throughly explore all four of the outlined areas.

What I hope to avoid in this tread:
Posts that contribute mainly to the posters post count.
Posts that get sidetracked into off topic areas.
Posts that center around/include bickering.

Basically:
What could Germany have done differently Politically
What could Germany have done differently Diplomatically.
What could Germany have done differently Industrially.
What could Germany have done differently Militarily.

The order is deliberate, as one follows from the others. A nation must first be led properly. The National Leader(s) must decide upon their goals. The path to achieve these goals must be attainable first industrially and only then militarily.

Looking forward to a lively and enjoyable debate;
Have at it!