Build every part of a persona fresh and only for that persona, starting with where it runs and how it connects. Do not create its accounts from your everyday browser "just this once": that first login is logged like any other and cannot be taken back.
- Define it. Write down what the persona is for, who it talks to and what it never does or says. Keep its name, username, the birthday you gave and similar details in its own password database, so you answer consistently.
- Give it a place to run: a browser profile or container for light separation, a virtual machine or Tails stick for strong separation, a separate device for maximum (browser separation, system separation).
- Give it its own network route. For a persona that must not be tied to your home address, use Tor; a VPN account used for nothing else is a weaker option. Never use the persona and your real accounts over the same connection at the same time (VPN).
- Create its email from that place and over that route, then use aliases for sign-ups (see below).
- Add a phone number only if a service insists, and use one that belongs to the persona alone (see below).
- Set up payment that does not lead back to your name, where the law allows (see below).
- Secure it with a unique password for every account and a second factor that does not depend on your personal phone number. Store recovery codes in the persona's own password database (Passwords).
- Give it a face of its own: a username you have never used, an avatar that is not a photo of you and appears nowhere else, and a short, generic bio.
Email: aliases or separate mailboxes
Aliases (forwarding addresses) stop websites from linking your sign-ups, because each site sees a different address (Email). They do not hide personas from the alias service itself: every alias in one account, and the inbox it forwards to, is linked in that company's records, and a legal order to it can reveal them. Some alias types also show their common owner to anyone: addy.io notes that aliases under one username can be linked by that username, while its shared-domain aliases cannot (addy.io FAQ). Custom-domain aliases point to whoever owns the domain. For a persona that must stay apart even from a request to one provider, give it its own mailbox and, if you use aliases, its own alias account paid for separately.
Phone numbers
Use services that need no phone number where you can (Messaging). When a number is unavoidable, give the persona a second number that is not in your name, such as a VoIP number paid for privately or an anonymous eSIM (Phones and numbers). Some mainstream options now ask for ID: new Google Voice numbers cannot make calls or send texts until the user uploads a government ID and gives a legal name and address (Google). For a separate handset, EFF's advice still applies: pay for it privately, never carry it with your main phone, never use it in the places you use your main phone, and never call the same people from both (EFF).
Payments
A card in your name ties every purchase made with it to you. Virtual cards let you give each persona or each shop its own card number, but if the card is funded from your bank account or the provider checked your ID, the issuer knows who you are: MySudo, for example, verifies your legal identity before issuing its virtual cards (Anonyome privacy policy). They keep merchants apart, not the bank or anyone who can demand its records. Cash, prepaid gift cards bought with cash and Monero leave far fewer traces; limits on anonymous prepaid cards and crypto differ by country (Virtual cards, Crypto). Use a parcel locker or pick-up point rather than your home address for physical goods.