I found this surfing the net.

What were, in your opinion, Germany's top mistakes in the following categories:
Battlefield (i.e.specific battles, campaigns or operations)
Non-Battlefield (i.e. production decisions, etc.)
Political (alliances, promotions, demotions, etc.)

Biggest Mistake...

Starting the war.

heh, yeah thats a good one^

biggest mistake? hmm, maybe Russia in a bad time.. Mostly that. And he needed to concentrate more on Britain. ANd his allie Italy? heh, was nothing..

Germany's biggest mistake is to invaded Russia. That's not a good idea. But if Russia invade Germany during Germans fighting in Africa. Well, that'd be a problem for Germany.

Operation Barbarosa.

He attacks the British,and when the enligh refused to surrender, he attacked Russia. Which was a bad idea starting a war on two fronts.

He should have asked Japan to attack Russia with him.

The biggest mistake was not finishing one operation before they started the next. If they had thrown there full weight at just on front rather than trying to take one on half dozen fronts at once then they might just had pulled things off. Just imagine what would have happened if Germany threw it full weight into North Africa and had taken all the oil fields in that area. It could have then brought Turkey into the War and attacked from the Crimea and from Europe when they went into Russia.

They commited three big mistakes:

- Postponed the battle in "Britain".

Germany had the military might to capture Britain through land invasion but they went for the second blunder (below).

- Attacked Soviet Union.

Lots of resources were used in war against SU but it was waste. If this war had not taken place then British would be defeated in African states too through heavy reinforcements to Rommel.

After this UK would not be a threat. And then Germany could proceed with invasion of Soviet Union but that too with assistance from Japan.

- Normandy Related.

And then Hitler sealed his fate with a 3rd mistake. He did not bothered about intelligence reports that Allied forces are planning invasion of France from Normandy and did not heavily fortified that region.

Originally Posted by TBA_PAKI

They commited three big mistakes:

- Postponed the battle in "Britain".

Germany had the military might to capture Britain through land invasion

They didn't have the military might that mattered.
Britain is an Island.
The Germans didn't have the naval forces to protect their invasion fleet from the Royal Navy.
While the Luftwaffe would have caused the RN serious casualties, it also wasn't powerful enough to stop the British fleet from reaching and destroying any invasion fleet.
There have been a number of joint Anglo-German Military Staff wargames post-war on this subject. In every wargame the end was the same, the invasion failed.

resources were used in war against SU but it was waste. If this war had not taken place then British would be defeated in African states too through heavy reinforcements to Rommel.
After this UK would not be a threat. And then Germany could proceed with invasion of Soviet Union but that too with assistance from Japan.

More resources couldn't be sent.
The OKH had actually looked into this before they sent Rommel to N.Africa. They found the due to the size of the ports and the logistical difficulties in getting supplies to this theater, they found that the maximum force that could be supplied in an advance to the Nile, was only 4 Motorised Divisions, which was the size of Rommels forces in 41-42.
Also defeat in North Africa while a major set-back wouldn't cause the defeat of Britain

- Normandy Related.

And then Hitler sealed his fate with a 3rd mistake. He did not bothered about intelligence reports that Allied forces are planning invasion of France from Normandy and did not heavily fortified that region.

Thanks to the deception campaign of the Allies, the German intelligence service was swamped with fake information. With the result that they didn't have a clue where the real invasion site was

Battlefield (i.e.specific battles, campaigns or operations)
Operation Barbarosa - a pure waste of men material and equipment

Non-Battlefield (i.e. production decisions, etc.)
Hitler's delay of Jet aircraft development

Political (alliances, promotions, demotions, etc.)
Not getting rid of Hitler.

A war with Russia was inevitable. It's either attack or be attacked.