- Use separate hardware. A cheap laptop and a cheap phone.
- Burn the receipt and chuck the packaging.
- Cash. Pay in cash.
- Buy from small stores with no CCTV, or better yet, from people like migrant workers.
- You can buy stored value cards (debit cards) without ID, and some you can load with cash at ATMs. (Also good to buy from travellers.)
- Once you have a debit card you can pay for data without going to a store.
- If you turn on your Wifi tethering and other devices are in range you have created an event in their logs. Just use a cable. If you must, change the SSID regularly and use Android 6 which has MAC randomisation. Never have any other SSIDs saved, especially not your home network.
- Turn the phone off when not in use. Removing the battery is advisable.
- Don't connect to 3G near your home or work or where there is pervasive CCTV or not many people.
- If your commute is logged (via your cellphone, number plate recognition / tolling, personally identified public transport like Oyster cards) then your location can be correlated against when your persona was online.
- It might seem that transmitting from different locations is a good idea. But not really, it gives a more unique history.
- Run Tor on the laptop. Run nothing on the phone, its just a radio.
- If you want to use Signal, get another burner phone.
- Invest in some numbered wafer seals or tamper bags. Keep your kit in them when cached.
- Don't tell fibs to federal agents. Record all interactions with them.