There are also some grammatical differences between British and american English, for example when you are choosing the correct preposition to use. Here are some examples:
You can phone us on 0800 123123.
He looked round the corner.
Her Accent is different from/to mine.
You can phone us at 01 800 555.
He looked around the corner.
Her Accent is different from/than mine.
Sometimes, Americans can miss out a preposition when British people would always use one, for example with the verb protest. British speakers would always use the preposition about: Some students were protesting about the war, but the preposition can be missed out in american English: Some students were protesting the war.