Did you know that your rucksack should not be anymore that 25% of your body weight. If you weigh 120 LB, your pack cannot weigh more that 30 LB.
Heavier equipment and food should be high and close to your back.
Items you might need during the day should be at the top of your rucksack.
Adjust the straps for your body height, making sure the hipbelt sits up on your hips and not across top of your thighs.
Check out more info under Downloads > Participants > Rucksacks.