Use a good quality backpack with various components. Organize your stuff for easy access. Make sure your bag is sturdy but not too heavy. You don't want something that will fall apart or weigh you down.
Talk to others who have backpacked. Ask for packing tips. Visit backpacking sites that have lists of what to take and where to go.
Research the climate of your desired location. You want to bring necessary clothes but you don't want to bring the wrong type of wear. Even in a hot climate, bring something for a cool night. In a cool climate, bring layers of clothing so you can take things off if you become too warm.
Pack overnight gear. You want a sleeping bag, a flashlight, mosquito spray and you may want a shelter. Pack good walking shoes, under clothing and socks. You need t-shirts and warmer tops or sweaters.
Bring your toothpaste and toothbrush. Put these items and soap into small plastic bags. Make sure you include sanitary supplies, toilet paper and deodorant. These items may be hard to find if you run out.
Pack your medication and first aid supplies in baggies. Make sure you bring mosquito repellent and sun lotion. You may want a small sewing kit as well.
Bring some food and water with you. You may want water treatment pills if you are going to a foreign country.
Bring currency and travelers checks. Pack all your travel documents and identification but leave a copy at home in case you lose anything. Put these items in plastic bags in case your backpack gets wet. Bring a camera to take photos of your trip.
