The essential list.
KEEP EVERYTHING UPDATED
Core software, plugins, themes.
The single most important measure.
USE STRONG UNIQUE PASSWORDS
Different for every account, stored in a password manager.
ENABLE TWO-FACTOR AUTHENTICATION
Wherever available.
REMOVE WHAT YOU DO NOT USE
Plugins, themes, old installations, unused accounts.
BACK UP, OFF THE SERVER
Regularly, tested.
LIMIT WHO HAS ACCESS
And what level.
USE HTTPS
Across the whole site.
MONITOR
Know when something changes.
THAT IS EIGHT THINGS
None requires expertise.
WHAT THEY PREVENT
The substantial majority of compromises.
WHAT NONE OF THEM COST
Money, mostly. Time and attention.
WHERE TO START
Updates and passwords. Today.