Shoulder check can be considered as one of the most critical bicycling skills which some adults have not learned yet. It does not matter if you are on a quiet residential road, a busy urban road, or just on a sidewalk. The skill to scan over the shoulder without making your bicycle swerve is important. The mistake an inexperienced rider will make is to pull the end of the bar with the left hand as he turns his head. This definitely makes the bicycle swerve to the left even before the rider has checked to be sure that it is save to move left.
Practice this bicycling skill in an empty parking lot. You could use the space lines there to help you keep track of how straight you ride your bike. Your arms must be bent slightly at your elbows. This is a very good position, in most cases, as it reduces the stress on your wrists, hands, and shoulders. It also keeps you from oversteering or wobbling. Drop your shoulders a little and focus on just turning your head and neck. If your neck has mobility issues, or you like to get a great view of what is going on behind you, take your left hand off your handlebar and rest it on your thigh. Keep in mind that it is your left hand that inadvertently pulls on the handlebar; the right hand does not push it. Practice this bicycling skills until you are able to do them with the least swerving.