Maybe sell Franco a bit better. Apparently, Mussolini was sent to persuade Franco to join in the war. Franco asked Mussolini if he would have joined... Mussolini's campaigns were going like crap at this time and he was definitely showing out as Hitler's junior partner. So Mussolini threw up his hands and said something like "I wish."
A more earnestly persuasive Mussolini might have brought Franco in. Franco might have been key to closing Gibraltar, which might have kept Britain out of the Med... who knows.
Avoid war altogether, of course, was Mussolini's best option.