Cool the cooler: If yours is stored in a hot garage or attic, bring it inside overnight so it can cool off before you start packing it.
Fill it all the way up: A half-empty cooler is half full of room-temperature air, which means the ice inside it will melt faster.
Use solid ice: Solid ice melts slower than cubed or crushed. If you can't find solid blocks, use reusable gel-filled ice packs. Line the bottom of the cooler, then pack food on top, adding cubed or crushed ice (in bags) to fill gaps.
Pack foods in order: Raw meats, fish and poultry belong on the bottom to avoid contamination. Seal them in plastic bags.
Keep it shut: Use a separate cooler to pack drinks and snacks for the trip.
Insulate it: Stow cooler in the trunk, away from light, and put a blanket or sleeping bag around it for extra insulation.
