I've run in 10+ running groups in Dublin, London, New York, and Paris over the past 7 years. Here are the characteristics of the most successful running groups that helped me to become an ultra-marathon runner.

Rain, hail, sleet or snow. As a long-distance runner, you want to run with a solid and consistent group. That's how you get strong at running long distances. Therefore, you look for a group that runs from the same place, at the same time all year round, no matter the weather (within safety reason). Taking an example from a group in Paris. They run on Mondays at 20:00 starting at Nation; 9:00 on Saturdays starting at the Jardins de Luxembourg. Always.

Changes to the starting time, the starting place and cancellations will have members taking their interest elsewhere.

For the people, by the people. Running in a group is not just a sport, it's a way to be part of a community. Part of this is being able to contribute your part and make running more enjoyable for everyone. The most successful groups I've come across, again like the Parisian group, are run by members.

This means that they are not sponsored. There is no membership fee. There isn't a complicated sign-up process. Everyone can be a pace leader if they like.

"If you want to go fast, go alone. If you want to go far, go together". Pace groups are important. The reverse of this is your whole group starts to run from the starting place and forms 'natural' pace groups. It does not work.

Ideally, there should be a range of pace groups e.g. 5min/km, 6min/km, 7min/km. This way you as a runner know that you will have your pack to run with. You will not be left behind. Equally, you know there is a natural path to progression from where you are to a faster group.

Running with people is nothing like running alone. You will run faster and longer with people around you to reassure you that running 20k for fun on a Saturday morning is normal. Tired legs? The story your fellow runner is telling you is worth sticking around for.

Put that cherry on top. After the run have some hot chocolate, beers, dinner. People run to have fun, to achieve something and they will continue to do it if they are surrounded by friends. The after-run chats are where the magic happens. People connect over other interests, talk about their travels, make plans to have parties, cycle, to help out with their renovations.

If your group can be claimed to have helped make connections and even babies, chapeau to you. I say you have a successful running group.