What can I do to make my them last longer…
That’s a great question… it kind of depends on what you’re doing with the origami. If it’s mainly for display purposes, you don’t have to do much… dust it gently every now and then and keep it out of the sun so the colors don’t fade. Obviously, you’ll want to display in a place that keeps out of harms way ;)
If you think the origami will be handled more (for instance, I’ve seen people turn paper cranes into earrings), then there’s a lacquer-like spray that people use, but I’m not sure what it is. I’ll have to look the next time I’m in the crafts store… anyone out there happen to know?