Start using an encrypted DNS server! I'm a big fan of NextDNS, quad9 is solid in my book too. Above this, the next step would be to start using a degoogled mobile OS along with FOSS apps. Its a marathon, so making changes slowly but consistently is the best way to approach it 100%.

Never sign in anywhere, or at least with fake, temporary accounts.

When ordering things send it to a pickup point, not home address. Preferable by fake name, but hopefully they don't want to see your ID.

Use a privacy focused email server.

Clear cookies after you leave a website, install an addon to generate a fake random browser fingerprint.

Never go on any website where you enter your real name and address.

Be sure to renew your vpn public ip address often. Be sure you can trust your vpn provider.

Turn off WiFi and Bluetooth when going outside your house so they cant track you that way. Stores do that nowadays.

Avoid being seen by public security camera's.

Make sure your friends and family don't post and tag your face or name anywhere.

Hope your cellphone provider, isp, healthcare provider, etc don't sell your personal data.

Basically impossible to not get tracked at all, but you can get quite far.

Get GrapheneOS, your mobile phone will be one of the best sources of data about you, and if you're on Googled Android or IOS, there's nothing you can do to stop google apps stalking you, which they have already had several lawsuits about doing it even when you disable it. GrapheneOS takes care of it by sandboxing google apps, so they can't do almost anything, along with really fine-grained permissiion control, i.e giving messenger access to only selected photo you want to upload, and nothing more.

As far as browser goes, I recommend Mullvad, and bundle it with their VPN. Not only can it be payed for by Crypto, it also means that almost every other VPN user will have the same browser fingerprint as you - fingerprint of the Mullvad browser, which is based on Tor browser and designed to be as unfingerprintable as possible, so it will be really hard to distinguish you using secondary fingerpriting, such as extensions or minor browser details.

Don't use Gmail or GDrive, ideally get your own NAS for file sharing and switch to something like Protonmail, which now also offers Drive. Get a domain that is vaguely company-sounding. Something like @techcorplimited.com, and create a catch-all email address, so any email sent to that domain will end up in your inbox. You can now use randomname.randomsurename@techcorplimited.com as your throwaway email address, and just randomly generate them for all services you use, while also making it believable to confuse even AIs.

Even when using VPN, don't sign into your accounts. You don't need to sign in to Youtube to tell it that it was you all the time, just remember your favorite youtubers and look for them by hand every time.

If you're really serious, look into https://www.qubes-os.org/