disable tracking-ID
disable telemtry
disable personalized ads
maybe don't use iCloud
turn off location
airplane mode frequently
use private mode in Safari
set search engine to DuckDuckGo
disable Siri stuff
adjust individual App settings
use Apps which care about your privacy, if avail (AdGuard, FE File Explorer, KeePassium, Magic Earth, Organic Maps, QuickScan, Signal...), unfortunately there are a lot tracking Apps without alternative :(
use a DNS blocker (like AdGuard) and Safari content blocker (AdGuard...) to protect against well known Ads and Trackers
feel free to use AdGuard to analyze your DNS traffic. E.g. many Apps contact app-measurement.com, www.google.com, graph.facebook.com I have blocked them, because I don't use Zuckapps and Google. It may breake features of the App, thats why they are not on filtersublists, but I don't care