>>559591Heaviest items (food, hard goods, etc) should be kept in the middle of the pack and towards the frame.
Sleeping bag and/or other soft items go at the bottom of the bag. This keeps heavier items from settling in to the bottom of the pack and dragging on the suspension.
I like to use other soft items like extra clothes to wedge around the heavy stuff and keep it from shifting around during hiking.
Items you will need quick access to (rain gear, first aid kit, snacks, compass) should be kept towards the top of the pack or in readily accessible pockets.