Unfortunately, one of the biggest mistakes you can make when learning American English is to imagine that there is such a thing!  There are many American Englishes, with regional variations in many parts of the country.   The differences I've noted below are all from experience, but they're not necessarily true everywhere in the country.   In the most unlikely places you'll find American's using "New Zealand" vocabulary rather than the "American" vocabulary I've listed below!   I made the same mistake when I first came to America regarding "American" pronunciation.   I knew that there was a Southern accent, and I assumed that everyone else fitted into a pigeonhole which I labeled the Northern accent.   Of course there's no such thing, instead there's a New Jersey (perhaps I should say Noo Joisey) accent, a New England accent, a Mid-Western accent, a Minnesota or Northern Michigan accent, and a plethora of others!