Runners are generally a pretty friendly bunch. All those great hormones your body releases after a workout help with that. Still, there are a few things to keep in mind if you’re going to attend a fun run or something like parkrun.
Unless you think you’re going to complete the run in 15-20mins (or less than 4-5mins per km in lengths other than 5km), don’t push yourself to the front of the starting group. At fun runs, your time won’t start until you cross the start line and at free events like parkrun, it’s just good manners.
If you’re walking or going slowly, it’s good to stick to the left. It lets the faster runners come past you. If you can hear a faster runner coming up behind you and there is room to get around you but you’re not exactly sure on which side of you they are running, then stick with your line you are currently running. Sure, the best thing to do is get out of the way, but if you can’t then it’s easier for the faster runner to go around you than to trip over you as you both move to the left.
If you need to stop to tie your shoelaces, adjust your clothing, fix something on your phone, then move over to the side, off the track if possible. You don’t need to trip others over.
Specific tracks events will have their own rules. Some allow kids/dogs/prams, some don’t. Some require you to join a starting group based on your ability to complete the course in a certain length of time, and some don’t allow you to listen to music while you run, usually due to the course crossing areas of traffic.
On the whole, running ettiquette is pretty straightforward and helps everyone to have a good time. So don’t be scared, get out there and run!