I do not know whether there is a bulletproof method to keep the data safe.
I am not a public person and the rules for that species should be quite different.
During the time I just follow a few simple rules.
- I use four email addresses and each of them with another password. All four passwords are variations of the same one. The differences are, let say, from “a” in one to “A” in another or from 7 in one to & in another. All changing with shift key.
- Two of these four addresses I use only to receive spam, to “membership” of whatever site ask for membership-ness to be able to have access.
- Each time I fill in by hand the username and the password, never let the browser to keep them. It is also a good exercise for memory. The only exception is the main account on the smartphone.
- Never, ever, I use my phone to take pictures of myself (I do not recognize as legit the word “selfie”). For this purpose I use a camera, a dumb one, with no FB or Twitter features.
- For shopping online I use one credit card, the same all time, only for that and not used for something else. Or I use PayPal.
- For all bank cards or credit cards I memorize their respective numbers and fill them in each time; no use of browser feature to keep them. Better exercise for memory.
- All papers with some personal data printed on them (even name, address, phone number, etc) I put in shredder.