It would have required a few things.
First more U-Boots, and even with the argument of more destroyers by the UK in response, remember that ASW tactics and technology was crap until mid 1941. So more U-Boots means more effect, even with more destroyers.
Georing needed to be dead or fired. He prevented as much as he could the Kriegsmarine from having the desperately needed long range recon aircraft it needed to make U-Boots more effective.
After the fall of France the Luftwaffe needed to concentrate on British shipping within fighter cover range, they did do this early on before going after airfields, they needed to do both. Plus hitting oil refineries stockpiles, so then U-Boots could concentrate on shipping to Eastern Great Britain.
Finally not stop at this until the UK had to sign the white peace that Hitler wanted before the Battle of Britain. With little to no oil, the RN and RAF are useless and critically tractors for farming would be out of fuel.
In the end the easiest option for Germany was to immediately send an invasion by the his paratroops to Great Britain after Dunkirk when the UK was weakest. In the end it was ironically Hitler's love of the people of the UK that stopped him in critical early opportunities to win. He simply did not want to kill any more Britain's or their culture than absolutely needed.