The British were engaged in war with France (the most powerful nation on Earth), Spain, a declining superpower, as well as conquering India, tussling with China and Turkey, and the odd spatt with Holland as well.
The Colonies began to build ships which were better than the British and which were manned by volunteers who were keen and eager and skilled too. They also only fought along their own coastline while the British had to come all the way from Europe to fight, although they had ports and cities in what is today known as Canada.
A great source of some of the differences can be found in literature. Two books I heartily recommend are (very reasonably) historically accurate novels from two very different authors, one who is a Brit who lives in the US today.
