Tough question. Let's see.

The German army was definatly stronger. British home defense after Dunquerk was weak.
German Luftwaffe was stronger than the RAF, however the RAF had some tactical advantages. They could withdraw from combat whenever they wanted to. So in the Battle of England it was undefeatable.
The Germans had nothing comparable to the RN.

The German strategy was foolish. The army tried to push responability to the Navy by saying that they have to guarantee a save crossing. Navy did the same and pushed resp. to the airforce. However, the air force was not able to beat the RAF in a air battle.

The right strategy would have been:
1) Preparation: Short attacks against the airfields and harbors in Southern England
2) Air borne operations against the airfields and then landing of the army.
The German paratroops would have been strong enough to take the airfields, I guess. The RAF would not havve been able to stop them. Standard proceedure would have been: heavy bombing at three o'clock, then at four or five landing of the paras. RAF had no effective night fighters and with a lot of German planes in the night sky they would not have had a chance to stop the German paras.
The question is would there have been a chance to reenforce the paras? The German fighter could have used the Brits airfields and screened the sky. Both sides would have had awfull casualties. Then the Germans had to cross the channel. The RN would have had to attack the flanks. There would be only little support from the RAF while the Ju88, Ju87 and He111 would have attacked the British fleet. A very interseting and decisive battle.
I do not know what would have been the end. Hitler was not willing to take the risk (although he always played risky!). However, this moght have been his last chance to win this war.