Quality acid-free, archival, lightfast materials are the first step for preserving your work. You can further protect your work with fixatives.
If you are not going to frame your work, an archival presentation binder or storage box is recommended. Finished art is best stored flat in a dry space. It should be protected from dust, dirt, and moisture.
If you are going to put your artwork in a frame, not only are the materials used important but how it is done is important also. You do not want your original work permanently mounted in a frame especially if you know you will change the frame in time.