Here's a question I received via email:
If I dream about people I don't know, does that mean I used to know them long time ago? Why do I dream of other peoples pets?
Dreams fulfill all sorts of needs for people. Basically and most importantly they are a way for the person to process their own stuff. So, even when you think a dream might be of others or prophetic in some way look first to see if there isn't some meaning for you personally in the dream.
After you have examined whether a dream is a personal message for you and decided that it was not then go after the idea that maybe these are folks who are visiting you or who you knew from long ago.
So, yes, it can happen that you are dreaming of people you knew in other lifetimes. It can also happen that you are exploring connections you have (everybody has them) with folks you don't personally know who with you are working on some sort of lifelong project. In the Michael teachings they explain that we do have these connections. They've told me that the person I am working with is a female presently living in China. I don't know her personally. Could be she and I get together occasionally in dreams to compare notes. Who knows? It sounds logical to me.
My advice would be since you have expressed an interest in your dreams is to begin keeping a dream journal. Keep a little notepad beside your bedside and before you go to bed promise yourself that you are going to awaken after your dreams and record a bit of them. What you record is nothing more than a couple of words. No detailed explanations. It is in the morning when you fill in the gaps. Those three words you recorded at 3 am will be enough to remind you what the dream was about. And, not spending a whole lot of time doing this at 3 am will ensure that you're not going to awaken anybody who is sharing your bed and you are not going to rouse yourself so much that you can't go back to sleep easily. Maybe keep a little book light next to the bed so you don't have to even turn on the bigger bedside light.
It might also take a week of the promising bit before you actually begin to awaken after your dreams to do the recording. I know with me that's what happens.
So, once you are in the practice of keeping a dream journal you might also notice that you're actually recording more than one dream a night. Good.
And, the next step would be to read, "Lucid Dreaming" by Stephen LeBerge. It didn't take me until I was just half way through reading the book myself when I began having lucid dreams. That is like going from riding the merry-go-round to flying along on a roller coaster. Big difference and a fantastic dream for sure.