Honestly, the best way I've found to maximize space is to think vertically. Don't just use your floor space - take advantage of walls, overhead space, even the backs of doors! Adding shelves, hooks, and hanging organizers can drastically increase your storage capacity. Also, consider multi-purpose items. Plenty of survival gear can serve more than one function, which helps eliminate redundancy.
While vacuum-sealed bags are great, especially for clothes and bedding, remember to switch them out and air them from time to time. We love mold-free stuff, right?
Keep in mind, too, that not everything has to be stored in your home. Think about whether you can safely and securely store some supplies outside or in a vehicle. Just be careful about temperature-sensitive items.
Got any specific items you're finding tricky to store? Maybe we could brainstorm some solutions.