Don't talk to strangers. Don't take things from strangers. Don't be too personal in conversations. Walk in the safe parts of town. Make sure you get contracts and agreements in writing. Don't give somebody something before they pay for it. Don't let your children play unsupervised or let them out late at night by themselves. Make sure you know where your kids are. These are things we have learned to do in the real world to protect ourselves. They are also, logically, the things we should doing online. Staying where it is safe, treating others with respect and avoiding those places and people who are ... unsavory.
Play it safe. No one can be too okay, especially in a place where damage (both personally and morally) are only a click away.