After a website suffers a significant data breach, the leaked data often ends up on the internet. There are several websites that collect these leaked records, and allow you to search your email address to check if you are in any of their lists. Firefox Monitor, Have I been pwned and DeHashed allow you to sign up for monitoring, where they will notify you if your email address appears in any new data sets. It is useful to know as soon as possible when this happens, so that you can change your passwords for the affected accounts. Have i been pwned also has domain-wide notification, where you can receive alerts if any email addresses under your entire domain appear (useful if you use aliases for anonymous forwarding)

When typing your password in public places, ensure you are not in direct line of site of a CCTV camera and that no one is able to see over your shoulder. Cover your password or pin code while you type, and do not reveal any plain text passwords on screen

Database leaks and breaches are common, and it is likely that several of your passwords are already somewhere online. Occasionally updating passwords of security-critical accounts can help mitigate this. But providing that all your passwords are long, strong and unique, there is no need to do this too often- annually should be sufficient. Enforcing mandatory password changes within organisations is no longer recommended, as it encourages colleagues to select weaker passwords

Most modern browsers offer to save your credentials when you log into a site. Don’t allow this, as they are not always encrypted, hence could allow someone to gain access into your accounts. Instead use a dedicated password manager to store (and auto-fill) your passwords

Avoid logging on other people's computer, since you can't be sure their system is clean. Be especially cautious of public machines, as malware and tracking is more common here. Using someone else's device is especially dangerous with critical accounts like online banking. When using someone else's machine, ensure that you're in a private/ incognito session (Use Ctrl+Shift+N/ Cmd+Shift+N). This will request browser to not save your credentials, cookies and browsing history.

Some sites allow you to set password hints. Often it is very easy to guess answers. In cases where password hints are mandatory use random answers and record them in password manager (Name of the first school: 6D-02-8B-!a-E8-8F-81)

If a site asks security questions (such as place of birth, mother's maiden name or first car etc), don't provide real answers. It is a trivial task for hackers to find out this information online or through social engineering. Instead, create a fictitious answer, and store it inside your password manager. Using real-words is better than random characters, explained here

Don’t use a short PIN to access your smartphone or computer. Instead, use a text password or much longer pin. Numeric passphrases are easy crack, (A 4-digit pin has 10,000 combinations, compared to 7.4 million for a 4-character alpha-numeric code)

When enabling multi-factor authentication, opt for app-based codes or a hardware token, if supported. SMS is susceptible to a number of common threats, such as SIM-swapping and interception. There's also no guarantee of how securely your phone number will be stored, or what else it will be used for. From a practical point of view, SMS will only work when you have signal, and can be slow. If a website or service requires the usage of a SMS number for recovery consider purchasing a second pre-paid phone number only used for account recovery for these instances.