Essentially Déjà vu is that experience where you do something and feel like you have done it before, to an eerie and almost physical extent. It usually occurs in a quick flash. While it is quite possible that you are psychically seeing the future and then redoing the things that you already saw in your dreams somehow, what is even more likely is that your life is so similar and monotonous that you do the same thing a lot more often than you realize. Déjà vu is simply an instance of you finally realizing that, though having this feeling in a dream is quite the experience indeed.
If you have a dream in which you experience déjà vu it means that you need to try harder to not repeat your life. Sometimes when you see déjà vu it is when you are doing something unsatisfactory. It means that you feel like you are repeating yourself to the point that you have become a bit boring or to the point that you feel like you are not doing all you can to keep yourself entertained. Don't live a boring life and don't fall into a boring routine. A human needs new experiences and needs to have fun in order to live a satisfactory life. This is the only way that this is possible. If you want to be able to make it just keep on going and make sure that every once in a while you are doing something new and exciting rather than just being boring.