We believe what we experience
We only really believe what happens to us individually so that is why I want to share my own story of precognitive dreams and how those dreams convinced me that we can see the future when we dream. When I was young, I remembered my dreams almost every night. Some were very interesting but some were just about things that happened during the day or boys that I liked. I would occasionally have distinct feelings of deja vu. I suspected that it was because I had experienced these events in a dream but it took me a while to prove that.
Dream Journals 
During my twenties I started keeping a dream journal which I still do today. Having a dream journal helps set the intention to remember your dreams and also you must write the dreams down as soon as possible before the memories of the dreams fade. I write all my dreams down even if they seem insignificant. One time before I left for a three day business trip, I decided to conduct a test. Before I fell asleep, I told myself, I want to dream tonight about what will happen on the trip so I can prove this one way or another. When I returned from the trip, I looked at the dream journal and found many details that were greater than coincidence. I was sold.