How To Efficiently Pack A Backpack
There's no one way to pack a backpack, but there are definitely more efficient ways than others. Packed carefully you can carry a whole lot with you on your trip. The goal is to create a well-balanced pack, one that won't shift around when you're moving.
When packing, always keep in mind that you want to pack layers not columns. Layers help with weight distribution and keep your back feeling great. Columns tend to force you to lean to one side, even if just slightly, and can cause serious back and shoulder discomfort before the day is done. There are three main loading zones: the bottom, middle and top. Each should be packed with two things in mind - what's needed early in the day and what will be needed when you get to camp.
The bottom of your pack is good for items not needed until reaching camp. This includes your tent, sleeping bag, sleeping pad, camp shoes, any nighttime clothing, etc. If using a foam sleeping pad you can use the loops underneath your pack to secure it and not eat up precious room inside your pack.
The middle of your pack is good for meals, stove and cooking gear, a bear canister if needed, etc. If you're packing a bear canister make sure to fill it with as much as possible to maximize the room in your pack. Surround loose items in your pack with your tent rainfly or clothing to prevent them from moving around. If using a water reservoir in lieu of Nalgene bottles, consider placing it in this zone as well, just fill it prior to packing. The goal in this zone is to create a center of gravity that will help your back over the course of your trip.
The top of your pack is a good place for rain gear and/or jacket, first-aid kit, water purifier, toilet paper, etc. Mainly things that you may need in a flash.
Most everything else can go in your pack's pockets and lid. Snacks, plicord, small electronics, headlamp, shades, bug spray, keys and wallet, etc. are always good in the top lid of your pack. It's also a good idea to pack your keys and electronics in small plastic bags before packing in the lid in case it rains. Hiking poles tend to fit fairly well in side pockets, but if you're going to be passing through tight spaces or under thick vegetation remember that they tend to snag.
Obviously everyone packs more or less items than what's included above, so find out what works best for you by practice packing a time or two before heading out. It's no fun having to unpack and repack once you're on trail. After a few times out take note of the things you've packed and never used. A lot of people tend to overpack and carry a lot of unnecessary weight and a few pounds of unneeded gear adds up over the course of many miles and elevation. And that's the not so secret sauce of efficiently packing a backpack.