Consider the websites you use. Some are more likely to be targeted by criminals than others.
Install internet security on your devices. There are many free or paid programmes available.
Don’t reuse the same password for all of your online accounts. Follow any advice on creating strong passwords. Consider using fake answers to security questions.
Review your social media privacy settings. Think about what other internet users can find out about.
There's info on The National Cyber Security Centre website.
The NCSC provides top tips for staying secure online.