I grew up in the Canadian Armed Forces and attended 7 schools in 11 years. Then I attended university in a co-op program for which I moved 15 times. I know a thing or two about packing, moving, and storage.
The first five rules of storing stuff
Rule 1: Don't store food.
And when you do store food, store it in air-tight containers.
Keep in mind that your commemorative slice of wedding cake is actually food. To moth larvae, wool sweaters are food. To silverfish, books are food. To a mouse or squirrel, everything en route to food is bedding.
Rule 2: Keep everything dry.
Beware of damp basements, leaky garages, or that one soggy brush or damp towel that gets packed prematurely.
Rule 3: Don't hide flammable stuff. Label it.
Ditto poisonous stuff and knives. A test question: If I saw someone toss this box toward me, would I catch it, or dodge?
Rule 4: Even if you're just storing stuff in the attic, pack and label the fragile stuff as if you were going to move.
You might move. You might sell the house. You might get so rich you can pay someone to schlep your gear to your glamorous new studio. Every time I store stuff, plans change. If someone else ends up shifting the boxes, un-gently and across great distances, will your stuff be okay?
Rule 5: Unless you're 100% certain your storage space is reliably climate controlled, don't store anything that can't freeze or bake.
To name just a few of the things that have caused me regret: Paint, snowdomes, aerosol cans,
media, solvents, wax, oil pastels, crayons...
Art-specific tips on storing stuff
Galleries, museums and people of unlimited resources can hire conservators to pack their art collections for climate-controlled storage in secured archives. Artists make do.
Tip 1: Store everything flat, not rolled.
Tip 2: Protect canvases from accidental punctures.
You may staple corrugated cardboard to the back of the stretcher temporarily (not permanent, reduces air flow). Don't stuff a small one inside a large one, or lean a short one against the face of a tall one. Those dents in the canvas never go away, and sometimes turn into holes.
Tip 3: Store canvases on edge.
Don't stack them like pancakes.
If you must store paintings touching, store them face to face rather than than face to back. There's just too much rough stuff on the back of a canvas.
Tip 3: Acrylic paint sticks together no matter how dry it is.
There's actually a Golden varnish you can use as a topcoat to prevent this, but no one does and you probably don't have time. You must put separator sheets in between, something clean. Newsprint is cheap and acidic; won't do much harm in medium term to acrylics but I could imagine it yellowing and staining a very pale painting. Tracing paper or pages out of half-used or cheap sketchbooks? For small work, I've used wax paper. The conservators will use acid-free tissue. The conservators have more money and fewer paintings than we do.
Tip 4: Minimize shuffling drawings.There is no spray fixative on the planet strong enough to secure drawing media to paper in the face of direct contact and friction. It's too bad none of us can afford to store each drawing on its own shelf. We stack them like playing cards and avoid shuffling the deck.
Store drawings face to back rather than face to face. I store drawings in portfolios, even portfolios made of big sheets of cardboard and duct tape. If I can afford it, I put sheets of newsprint between them. If I'm rich, I put pieces of cheap white paper in between them.
And it should go without saying but...
Tip 5: Label everything.
We all get tired and rushed; we all compromise on labelling; we all regret it.