When I am writing a contraction, I have to think of the meaning to help me think of the two base words. If it is a ‘not’ contraction, then I cross out the ‘o’ in ‘not’ (and in ‘can’t’ we also drop the ‘n’) and replace it with an apostrophe. Except for the word ‘won’t’ which is a bit trickier. I write the two words together as one word. A contraction is something we use when characters are speaking or in informal writing.