You won't believe this mysterious “telegram” from the future but please let me assure you that, should you take my advice below, you will achieve all of your goals and the Third Reich will live long into the 21st Century:

Strictly maintain your non-aggression pact with Russia. In fact, periodically sweeten it with physical gifts for the Russian people together with some Eastern European land. Realise that “Lebensraum” has to mean Western and most of Eastern Europe (for now). Stalin won't be around for much longer. If you absolutely have to invade Russia (again — don't!), get the Japanese to attack from the East too (they will as they'll want the oil) and don't do it in the Winter.

You've only been building your military since 1935 (due to the Treaty of Versailles). Four years is not enough time to amass the force you need to do what you want to do. In particular, your navy is too weak (except for your u-boats). Think ten years and build some carriers to project power.

Stop with the Jew hating. This is not only because the Holocaust will take away all moral authority from Germany, it's because Jews are clever; with Einstein and Heisenberg on-side from mid 30s, a fission bomb can be made years earlier. A quick demonstration — perhaps nuking Northern Ireland with a low kiloton yield (say 8 kilotons) will stop all Allies from invading you. If it doesn't, nuke Glasgow with a 15 kiloton yield. In fact, help the Jews by becoming a Zionist; actively help them establish the state of Israel; work with the British/Americans on this. Treat as the highest priority in the war the destruction of the British Expeditionary Force (basically their entire army) in Dunkirk by the Luftwaffe. Do not be swayed by British diversionary tactics in Calais.

Throw away Operation Sealion. Invading the UK won't be easy (they still have the world's largest navy and one of the largest airforces) but you just won't be able to hold it and it'll give the US a reason to enter the war.

Forget about your giant tank/railway gun programme. That Great Gustev you have or are working on will only be used a couple times. Concentrate upon making your excellent Tiger Tanks lighter.

Let your Generals run the war. You won't like this but Lt Col Richard Thornley (one of Britains's top experts on Germany) wrote: "As a strategist, Hitler has been of the greatest possible assistance to the British war effort...he is still in a position to override completely the soundest of military appreciation and thereby help the Allied cause enormously."

Forget about Italy. They will only help you with Austria and Yugoslavia. You’ll get them later. Everything else they do e.g. Greece, North Africa will be a hindrance to you. Mussolini is not a winner. If you think you need North Africa to control the Mediterranean, you don't, you need Gibraltar. Make nice with Franco and jointly divest the British of it.

Be allies with Japan but specifically word in the Tripartite Pact that no-one is to attack the US. Currently it doesn't mention the US at all. This will leave the Japanese to make an existential miscalculation that will ultimately ruin Germany.

Realize that the Age of Empires is in it's death throes. Once you've captured Western Europe and most of Eastern Europe (except the UK), switch immediately to a mode similar to the US; one where they are an empire in all but name. Their power coming from strong industry, science, economic power and exported culture. Germany needs to spend millions subsidizing and exporting the German Arts. Think client states driven by the carrot not the stick. Don’t treat conquered people in the East as “Untermenschen”; they will turn against you. Put a German astronaut on the Moon for all European people.

----- NOTE to Self