Preservation extends what you already have; rotation makes sure it's still good when you need it.
Canning (water bath): Safe only for high-acid foods — fruit, jam, pickles, tomatoes with added acid. Low-acid foods (vegetables, meat) require pressure canning; botulism risk in low-acid foods processed with water-bath methods is real and not worth the shortcut. Follow tested recipes from a source like the USDA's National Center for Home Food Preservation rather than improvising times or ratios.
Drying/dehydrating: Works for fruit, vegetables, and jerky. Meat must be dried at a high enough temperature (or pre-cooked) to kill pathogens — a home dehydrator set below ~160°F for meat is a food-safety risk, not just a texture issue.
Salt curing: Effective for meat and fish, draws out moisture that bacteria need to grow. Requires curing salt (with nitrites) for anything beyond short-term refrigerated curing, to control botulism risk specifically.
Rotation discipline — "first in, first out": New stock goes to the back, older stock moves to the front. Label everything with acquisition or expiration date on the outside where you'll see it while grabbing something else. An emergency stockpile that silently expires over 18 months is a stockpile you don't actually have.