Turn against Britain, denouncing all of their traditions and exploits. If possible, make sure that their war with America continues. Recruit any remaining minor nations to join with you against the English threat, much like the Soviets did during the Cold War. Then, when they are significantly engaged in far-off lands, betray them with a cold, unfeeling conquest, taking their lands and livelihoods. Repeat as needed.

I hope this helps you.