Q: What are the major differences between British and American writing styles—in terms of sentence structure, vocabulary, etc.?

OK, are you sitting down? Then let us begin:

In London in the summer of 1982, as I waited for my university studies to begin, I worked at various jobs—including, out of curiosity, a spell selling encyclopaedia sets door-to-door (at that time, of course, encyclopaedias were still only in print form).