start writing down your dreams, keep a journal or a recorder by your bed, write, sketch, or record your dream the second you wake up since 90% is lost in the first couple minutes. we dream about 5 times a night, but only remember the most recent one, as you get better with your journal, you can train yourself to wake up after dream cycles.
that being said, the difference between a vision and a prediction through your dream is hard, while a prediction through dream interpretation, or perhaps you see a friend sick and a week later they are. if it's a prediction, it's typically reoccurring until the event happens then you'll never see the dream again, and is precisely how you dreamed it. if you're walking down the street and find a puppy but before that you were flying, the one spot where you find the puppy would be the prediction and the flying is a part of the dream.
an example [a positive example] i moved to the town i'm in about 10 years ago, and for two year i'd have a dream every month where i'm walking with friends, there's a bunch of strange things, like the close, and one friend kept running through traffic, but at one point one friend said 'hey, let's go to that new candy store' so we run down a side street, and into this building into a candy store with red walls, a white and black tiled floor and wooden shelves, a few years of this kept happening, then one day my friends and i were walking through town and my one friend mentioned a new candy store, she ran through the middle of the road, nearly getting hit, and we chased after her to the exact same building as my dream, we went inside and everything was identical.
my point, your entire dream probably won't come true, but a certain part of it, the most memorable vivid part, is typically the prediction.