Well, I have some scenarios in mind:
1) Get bold (more lol) at the Munich Agreement and flatout tell Chamberlian that Germany's ambition is to regain everything lost in Versailles minus Alsace-Lorraine (this one being excempt because it would never get accepted). You see, most of the West saw Germany as having the right to reclaim what was lost to Versailled, what really turned everyone against Germany was no the annexations themselves, but Hitler repeteadly going against his own word and violating international agreements. It is a long shot, but if the UK agrees to some sort of plan that they will keep themselves out of war if Germany only limits itself to Versailles gains then likely Germany can invade the Sudeteland and then Danzig with impunity. OTL Germany got a "free" invasion card when they invaded the rest of Czechoslovakia and got away with it until he broke its word once again and invaded Poland. Taking this in consideration, Germany can likely invade Czechoslovakia and then the USSR withut war in the West. Without the looting of France Germany would be weaker but so would the USSR and a 1 front war would help tremendously.
2) Similar to 1. Reach the original Munich agreement and respect Czechoslovakia, there was important industry and gold there, but going by some comments in a thread where this was discussed, the Czech government was already a quasi puppet to Germany and what they asked they got. Then use your "free invasion without war" card and attack Poland instead. The allies will be mad, but just like OTL they will not go to war. Then invade the USSR, the allies are not going to go to war over protecting the USSR, no way. One of their dream scenarios was to have the USSR and Germany duke it out and destroy themselves in the process. Hitler can invade the USSR now in 1939 or 1940. Again, without Czech industry (unless Germany can bully them into becoming an ally) and France looting Germany is weaker than OTL, but so is the USSR which went through the purges and having just a 1 front war would help a lot.
3) Go as OTL, with the exception you capture the British Army at Dunkirk. Then sue for peace publicily and officially. Churchill was already under tremendous pressure to agree to peace as it was, it was a very close call with Churchill having to promise Halifax scenarios in which he would agree to peace. A disaster at Dunkirk can likely shift the situation. Almost guarantee to succeed, if not just give generous enough peace terms until Britain agrees.
4) If things go per OTL and you can't crush Dunkirk, then offer Britain in a very public an official way that you will be withdrawing from everywhere minus Poland in exchange for peace. Harder to achieve without the Dunkirk card, but there is a shot it would work.
5) Accept the USSR into the Axis, shift Lebensraum to Africa instead. Stalin got very close to joining the Axis, he actually made a final proposal to do so, which Hitler alone vetoed against the advice of nearly everyone:
en.wikipedia.org
Give Stalin as a condition to join the Axis to declare war on Britain. A huge chank the sinks Britain's morale, fighting a Germany that controls everything from Calais to the Warsaw was already a daunting proposal. Having your only continental ally join your enemy, and now face a combined enemy that holds land from Calais to freaking Vladivostok would simply look impossible, even Roosevelt would likely begin sweating at the prospect of entering the war. If the UK refuse to make peace, then just pummel it in the Mediterranean until they agree or just fight a defensive war and keep killing British military and shooting down planes until they get tired. They will eventually HAVE to come to terms. This is in my opinion the 1 war winning strategy Germany could had, used that gives him a guaranteed victory.
6) If you must go for a 2 front war, then end the war quickly. There is evidence, albeit not very good that in 1941 Stalin was willing to come to terms with a Brest Litovsk style peace. Hitler of course would have nothing else but A-A line or the Urals. If Hitler or the military can appreciate just how bad the situation in the USSR can get, when you are rampaging through the USSR sue Stalin for peace with Brest Litovsk terms. While not guaranteed, there is a good chance he would accept. The effect of this would also be that it would cause a shock at Britain and worldwide, while Germany dodged a bullet, it would look to everyone that Germany defeated the USSR in less than 3 months (even less time that Hitler anticipated). It would look like a Battle of France victory on steroids. Now Britain's only potential ally on the continent has been crushed, Germany took out with utter ease 2 out of the 3 powers that could oppose it aside the USA. Sue for peace with Britain, if they refuse just fight a defensive war until they come to terms. To me this scenario is the second most likely victory chance for Germany.
7) Bomb and mine British ports in particular Liverpool. I am not really informed on the chances of this strategy, but I have seen it posted here as a way Germany could had used to defeat the UK.
8) Follow a Mediterranean strategy against Britain and scrap Barbarossa. Not sure how well this would work, but I think it has good chances of working.
9) Starve the USSR into submission. Again, I don't know how plausible is this, but I have seen people here claim that Germany OTL plummeted food production in the USSR by occupying some of its richest farmlands, and that had Germany just kept the occupation in those areas longer (the Kuban region I think) the USSR would had eventually starved out and be forced to give Hitler what he wants.
In all scenarios apply the rule: Avoid war with the USA at all costs.
