Store water in a collapsible bottle. This container is 80 percent lighter than a hard-plastic one. Freeze it first so it will keep cool. (Platypus one-liter bottle, $9, llbean.com.)
Use sleek food storage. Go with a plastic bowl that flattens accordion-style when empty, leaving less backpack bulk. (Four-cup containers, $17 for two, tupperware.com.)
Pack crushable snacks in a Ziploc bag. Fill it with chips, then slip a straw into the top of the nearly closed bag and inflate. Remove the straw and seal to create a cushion.
Wrap your sandwich in a double-duty sleeve. This reusable liner multitasks as a cheery gingham place mat. (Wrap-N-Mat Wrap, $10, wrap-n-mat.com.)
Clean up responsibly. Clip this tiny gadget onto your bag so the only trail you leave is footprints. (Sunshine Kids 12-bag dispenser, $4 for three, bedbathandbeyond.com.)
If you plan to wander off the beaten path in search of the perfect lunch spot, pack some colored chalk so you can tag trees or rocks along the way and find your way back. (A compass is a good idea, too.)
2 of 3Dana Gallagher
For the Beach: Pack a Little More
Dragging a cooler across the sand is a real, well, drag. Instead, carry a light yet satisfying assortment of foods in a modern insulated basket.