1. Unique Email addresses and passwords for your account. Do not tell anyone your password.
You can use a official password manager like Lastpass or KeePass.
2. Enable 2FA
Like Google 2FA, Authy
3. Make sure the domain name is www.top.one/www.top1.one.
4. Do not click links and open attachments in Emails.
5. Subscribe to a good antivirus software and keep it up to date.
Like Bitdefender Endpoint Security Tools
6. Secure your Email account and phone and use PGP on top of it
Like using a secure Email provider; Enabling fingerprint and passcode lock.
7. Secure your computer
Do not install too much software on your computer. I recommend using a dedicated computer, install Linux on it, the Chrome browser, a password manager plugin, and nothing else.
8. Secure your internet
I recommend always using a wired connection if possible. If you have to use a WI-FI, route all your traffic through a VPN.