It’s super simple. Always use HTTPS. Your ISP will know where you went but won’t know what you’re doing. Use a VPN. If you just want to hide from the ISP a free solution is fine. Want to really be safe pay for a VPN and make sure they don’t keep logs of your traffic. Always use a VPN when on a free open WI-FI network. Don’t use google. Use DuckDuckGo. Simple tips but nothing is truly safe.