I advise people who are new to cas to do things that they like the reason for this is because if you do something that you really enjoy or like you wouldn't feel tired or resenting doing CAS, it'll feel like you're doing a hobby and makes CAS that much more tolerable. I also advise new people to document every via picture because you wouldn't lose any evidence  of doing CAS if it's on your phone or Camera.  You should also try to connect your project with the IB learner profile because it'll help you think and inspire ideas for your CAS projects.