There were many things the Germans could have done differently. The biggest obstacle for Germany to win the war was Hitler being the supreme commander.
Hitler was a fanatic and an awful commander. The holocaust required a great amount of resources but his anti-semitism is who he was and how he unified the country from the depression so there is no way we can remove that. Hitler did refuse to have women work in the factories. The Russians, along with many other countries, used everybody to work in the factories and were capable of producing double the tanks in a month than the Germans.
When Hitler saw the 262 jet fighter he demanded it be used exclusively as a bomber. It delayed the production for 1 and a half to 2 years of the me-262, which would despite the setback, still become the first mass produced jet plane in history. They eventually went around Hitler and made it back into a fighter. Imagine jet airplanes obliterating the bombers hitting germany, and germany controlling the skies.
Hitler also messed up D-Day because he would not allow 3 of the 6 tank divisions to be moved in Normandy without his consent. Well, Hitler slept late into the morning on D-Day. Around 11:00-12:00 A.M. late.
Hitler made many mistakes. If Hitler had not screwed up the me-262 and D-Day, Germany could have survived longer. If the war would have gone on for 1 more year, Germany would have had the Atomic bomb. Plus, they had a stealth jet bomber that was successfully flown and was being modified for strikes against the U.S.
Then there is the Russian front and ordering that no one surrender or retreat. We can list his failures for a long time.