There's no positives to come from a Trump presidency on foreign affairs.
People point to better ties with Russia.. but the US doesn't need better ties when Russia are being the aggressors in almost every circumstance and improving those relations will give Russia a foot in the door to press Trump and the US even more. If they aren't careful, Trump could get horribly played by Russia in the next while. Not here for that.
Pushing China is also not the way to go. They'll almost definitely bite back especially on something like Taiwan. Obviously Taiwan deserves independence but inflaming China right now is really not a clever idea.
He better hope he can knock out ISIS as that's really all he has right now so if he fails to do that in the next 4 years (or at least improve the situation) then

A terrorist attack would be damning for him especially if it happened after all of his measures to prevent it from happening were implemented.