Group riding can be tricky. Don't ride side by side. Give yourself lots of room. Lead rider is in the left half of the lane second rider is several lengths back an in the right side of the lane. Again leave lots of room for panick stops or to avoid hazards on the road.
The biggest though is to not let the group dictate your pace. If you are following more seasoned riders and are trying to keep up you have a better chance of going into a corner too fast. If you have to, let the group ride ahead,you can catch up later. It's better than them wondering where you are only to find you later crashed in a ditch somewhere.
Other than that have fun.