Make a list of all items that you plan on packing for your overnight trip. For some people this might be very simple and very basic, such as, "a toothbrush, pajamas and a clean shirt." For others it might be more involved, such as "pajamas, bathrobe, slippers, clean underwear, toiletry kit and a curling iron."
Place all the items that you plan on taking for the overnight trip on a flat surface like the top of your bed. Fold the clothing items and stack things on top of each other as if you were packing for an imaginary trip.
Asses how big your pile of stuff is by comparing it to something. For example, your stuff might be the size of a breadbox or the size of a small mini-fridge.
Pick out a backpack that has a size that's 50 percent larger than your pile of stuff. This way it will easily accommodate all your stuff, as well as have room if you want to take anything home from your trip, such as a souvenir.
