In 2018, I became Mintlodica. Mint, my favorite hue, and melodica, the instrument anime manic pixie dream girls play. My username used to be my name. In retrospect, that was a bad idea.
I'm glad, and a bit mad, to report abstracting yourself behind a handle works well. They may know me as Susan, but they harass me much less. To them, Mintlodica is a Creative Studio not a person. When it comes to naming, not inviting yourself to "be open and out there" helps maintain your privacy.
Anything you can stand to delete, you should delete right away. Deleting Facebook was one of the best decisions I've made. Many sites make it a pain to go through their account removal process. Turns out, those sites are the ones you need to worry about the most. If you have historical data on any platform, consider finding a script to scrub it. Time and time again, we can't trust the corporations to do this for us. After all, this is a world where not even your disappearing content disappears. We need to be vigilant.
p.s. This is meant to be a relatively short guide, one highlighting the most effective things. You can be even more thorough with your privacy. This book is good for all, not just good for girls.
From here, it's maintaining good habits.
Only give as little information as you need to use the site. When services ask for data like your birth date, stop yourself for adding it. Half the time, the form validates without this information. The other half, you should enter dummy data. Unless you're renewing your Government Issued ID, they don't need this. Same when it comes to apps asking to get your location. It turns out, the app will still work!
Create a few pen names. I have a Yelp account using one of my pen names. I want to support the small businesses I patronize without compromising my privacy. It's easy to triangulate where someone might live based on a handful of data points.
I now use DeleteMe, as the time and energy it took to do the upkeep myself was significant. They also have a thorough help section where they walk you through each public record aggregrator. If you don't want to delete all the data yourself, this is my DeleteMe referral code for 20% off.