Group members should actively participate in the meeting by critically assessing each colleagues work and making helpful suggestions. The purpose of these meetings is to foster discussion, generate new ideas and suggest ways to improve each other's work.
Some points you may consider are:
Are the conclusions valid ?
What does each the figure add to the paper ?
Could the figure be be better organized or presented ?
Is data missing or how can the paper be strengthened ?
Should figures be added or removed ?
Is the purpose of the study clear ?
Are the results clearly presented ?
Is the data convincing ? What is missing ?
Is the conclusion valid ?
Anything else that may be helpful