Privacy and security tips
Delete unnecessary accounts to reduce your online footprints. Setup
two-factor-authentication wherever possible. Use complex and long passwords, and
use a password manager (such as Bitwarden) or secure note (such as Standard
Notes) to write down your passwords. Use specialized tools to create complex passwords or
passphrases; your password should look like: LeIH}gZ9We#Z5X or even more
random and longer.
You can also use openssl or gpg to generate random passwords:
$ openssl rand -base64 30
C4/uLe3fJwhyatLO0yuLX2oMQZ5scnvWXHxFrjmi
$ gpg --gen-random -a 0 90 | fold -w 40
0cC0ba287A5EE+ctd1lQAGWKXZIcZhZXbe+47/bu
eCpRDZRhQrzsaQS5Y0vVPpLAXAuNgksb3J8Xd2kF
OwJzQBhgP6l+yy1V1qoa1L/VJcpNYQidhfAKkKOu
Keep your devices and apps up to date: One of the best thing you can do to keep your devices safe is keeping them up to date. Go to settings, and install all available operating system and app updates.
Metadata
Be mindful of metadata when sharing various files. For example, your photos may contain geo-location, camera (phone) model; your office files may contain names of your collaborators. If you are on Windows, you can open the file properties from the right-click context menu, see the metadata and remove them.
There is a cross-platform exifdata removal tool particularly for images - https://github.com/exiftool/exiftool. If you are on macOS, you can install it using homebrew.
File integrity checks
When you download various installers, it is good idea to verify its SHASUM. On Linux and macOS:
shasum -a 512 installer.ext
On Windows:
CertUtil -hashfile installer.exe SHA512
Redact sensitive information
Use professional tools to redact documents and images to hide sensitive information. Adobe Acrobat Pro has redact tool to remove text and other data from PDF files.
Encryption for local and remote files
Use full disc encryption for your computer/laptop hard drives. Mac FileVault, Windows BitLocker, and Linux LUKS are good options. You can also use full disc encryption tools like VeraCrypt. When uploading sensitive information to popular cloud storage providers (Dropbox, OneDrive, Google Drive all allow files to be reviewed by certain employees and subjected to law enforcement requests), encrypt using AES-256, or PGP encryption. You can have a look at Cryptomator for encrypting your files before uploading to any cloud. Create regular backups of your data, always encrypt locally before backing up to a cloud service.
VPN
When you use a VPN, your traffic is visible to your VPN provider, it is important whom you can trust. If you are on a public WiFi, it is always a good idea to use a trustable VPN service. I believe ProtonVPN is a good option. Today's internet is full of trackers, using a VPN will help you hide your real IP address. You can also use https://www.startpage.com along with its anonymous view for the same purpose. TOR is another option, however many popular websites may not function optimally via TOR.
Email
Use privacy friendly email services such as ProtonMail. However, note that ProtonMail is private but not anonymous; they might share various metadata (not your email content and attachments) with law enforcement agencies. If you are comfortable with technical inconveniences, you should setup PGP encryption. If possible, communicate less via email and use services like Signal (enable disappearing messages). Email providers collect more metadata than Signal.
Browser and search engines
Use privacy respecting web browsers like Mozilla Firefox or Tor, and search engines like https://www.startpage.com or duckduckgo. Clear your browsing history and cookies regularly or set to clear when you quit browser.