There are a few things that you can do that are a good place to start, and will give you the basic measures needed to make sure your materials are safe.
Do not store your important media, paper, or photographs somewhere that it could be easily damaged. This includes floors, top shelves of closets, under your desks or anywhere that you wouldn’t store something that you wanted to keep safe. Aim for six inches off the floor (on a shelf is fine). Cool and dark is best. If you decide to store in an attic, make sure that it has some climate control and that you do not have a leaky roof. If a basement is the best option, be especially careful to keep your items away from any places there could potentially be leaks or flooding. Clearly label the boxes with at least a date and description.