For the kids we just make sure all their devices have the restrictions set up to limit which web pages they can go to. We also regularly do a check of their internet history to make sure they aren't going anywhere they shouldn't.
Now that there is a heavy reliance on the internet for school work, the school regularly runs sessions for parents and kids on internet safety. I think it's mandatory attendance at least once a year at my kids school. Maybe ask the school if they run something similar, as we've found the ones we've sat through with our kids to be really informative and up to date with the latest information and safety tips. And since it's coming from the school, with a consistent message to all kids and parents, our kids are more likely to follow it because it's not just Mum and Dad being overly protective.