Select a bag with a shoulder strap of a comfortable width for your shoulder. Because a shoulder strap sits on the muscles located between your spine and your shoulder, it will invariably place significant pressure and stress on these muscles. If the shoulder strap is too narrow or too wide for this area on your shoulder, it will begin to feel uncomfortable quite quickly. Test shoulder bag straps prior to making a purchase to ensure the width of the shoulder strap feels comfortable on your shoulder
Look for a bag with shoulder straps that have gripping materials on the underside of the strap. These gripping materials will enable you to place the shoulder strap on your shoulder and it will stay where you place it. If the gripping materials are ineffective, you will constantly be repositioning the shoulder strap on your shoulder and this will lead to fatigue and discomfort
Choose a bag with shoulder straps that flex with the shape of your shoulder for greatest comfort. Once you place the shoulder strap on your shoulder in a comfortable position, with effective gripping materials and a flexible strap, the bag should stay in place on your shoulder as it fits comfortably around the shape of your shoulder
Fill the bag with the items you will carry in it. An average weight for a shoulder bag is between 15 and 20 pounds. As long as your shoulder strap meets the above criteria, you should not have difficulty carrying around a shoulder bag of this weight on your shoulder
Place the shoulder strap onto your shoulder so the width of the strap is directly over the muscles of your shoulder (between your clavicle and neck). Bend your arm at the elbow and support the bag slightly by resting your arm on the bag and holding onto the front strap
