Of course, some dreams come true automatically, without much effort on your part. You dream about walking to work, or to school, which is something that you do five days a week. You dream about brushing your teeth, which hopefully you do at least once a day.
Other dreams don't come true unless you fight for them. You dream about becoming a published novelist, you dream about becoming a doctor, but those dreams don't come true unless you are an active participant in making them come true.