The two most common prepositions used after the verb “think” are “about” and “of.”
They are very similar, but there is a small difference.
Usually when you think of something, it is a brief moment – just a few seconds. It is
also used for opinions. When you think about something, you are considering it for
a longer time – like a few minutes or more.
▶️ Every time I hear this song, I think of my mother.
(thinking for a few seconds)
▶️ What do you think of my new haircut?
▶️ I’m thinking about moving to a different city.
▶️ I still get angry when I think about all the rude things my sister said to me.
(thinking for a few minutes or more)
Common error: Don’t use “think to” for “considering.”
▶️ I’m thinking to do an intensive English course in Canada.
▶️ I’m thinking about doing an intensive English course in Canada.