What you carry on your journey depends on how far you're going, when you're going and where you're going. When stuffing your backpack, think about weather, terrain, altitude and the general environment. For example, if you're hiking the Arizona Trail in Utah, you'll need less protection from insects than if you were hiking in the Oregon backcountry in July.
Hiking in the winter means dressing in layers instead of bulky coats and sweaters. You want to keep the moisture from your body to reduce your chances of hypothermia. As such, stay away from cotton shirts and pants and go with wool or synthetic fabrics such as polypropylene. Synthetic fleece and nylon will help your body "breathe" and keep you dry [source: Appalachian Trail Conservancy]. A waterproof outer shell is also essential. Summertime hiking means T-shirts, sun hat, insect repellant, sun block and shorts. Don't forget your raingear and some warm clothes for the night [source: backpacking.net].
It's a good idea to keep your backpack as light as possible for a long hike, although it's easier said than done. One way is to keep track and weigh every piece of equipment. When possible, replace a heavy piece of equipment with something that is lighter yet works just as well [source: GloboTreks].
In addition, take what you need, but nothing more. Keep the books and personal electronics to a minimum. Do you really need a laptop or an iPad in the wilderness? You certainly don't need jewelry, extra toiletries, more than one jacket or bulky towels. Reduce your load by sharing it with your hiking buddy. Pack juices that you can mix from powder [source: GloboTreks].