I consider premonitions separate from dreams.
I've only had one 'dream' that came true, and that was when I was 12 and was so badly frightened I went straight to my grandmother, a witch, who made them go away.
She's not in this world with us any longer, and lately I've been getting very heavy feelings about something, very vague, and an event will come to pass that's in line w/the feeling I've had.
It's started to get linked w/a particular song, and when I hear that song - by chance - I know soon what will come to pass, but not very specifically, if that makes sense, at least not yet.
This is how it started when I started to 'see' spirits, so I expect this will get stronger w/age.
I think for the most part dreams are the brain's way of trying to make sense of and cope with our emotional energy.