Stay out of large packs of people. At the start line, let the “frisky” riders clear out. If you find you are in a large pack, particularly at the start, maintain a safety bubble between you and the riders in front of you. Most large crashes of riders (not in a paceline) occur within a few miles of the start line when someone swerves to miss an obstacle or drops a water bottle and other riders around them overreact.
Stay away from inexperienced riders. Avoid people who swerve or are not riding in a steady, consistent direction. Avoid people who “pedal, pedal, coast”. Their speed and path will be erratic and these habits frequently represent inexperienced riders who will likely do other unpredictable things.
Pass with care!! Give people plenty of space when passing and announce that you are going by. Pass only on the left of a rider. Look behind you before passing someone in front of you! Don’t pull out to pass if there is a car or another cyclist overtaking you from behind. They may not anticipate what you are about to do.
Stay focused on the road in front of you. If you need to check your directions, stop and pull over to study the map. Monitor riders in front of you for unexpected behavior. Riders may suddenly stop without pulling over, signaling or announcing their intention.
Single file is safest. Try to avoid the temptation to ride side by side. It is easier to accommodate the cars and other cyclists if you are not taking up half the lane (or worse). Other riders who want to pass people riding two abreast will almost have to go to the centerline to do so.