Implement protections to restrict access to malicious and fraudulent websites.
Your network is your border to the internet, understand it and protect it!
Ensure you change the default password for accessing the admin portal of your router and change the wifi password. If you have the option, create a guest wifi access point and give that password to guests.
Most 'good' Internet Providers will have some kind of basic filtering, so if you try and access 'dodgy' websites, they should block you, but go a step further and use a DNS service that you can control.