Practical steps.
WHAT TO DO
Keep it updated Use a screen lock with a short timeout Use a standard account rather than an administrator one for daily work Encrypt the drive, where supported Use reputable security software
THE STANDARD ACCOUNT POINT
Daily work under an administrator account means anything that runs has full access.
A standard account contains the damage.
THE ENCRYPTION POINT
If the device is lost or stolen, encryption is what keeps the data unreadable.
Most current systems offer it. Enable it.
WHAT ELSE
Remove software you do not use Review what starts automatically Do not install software from unknown sources
WHAT TO BE CAREFUL WITH
Browser extensions, which can read everything you do Anything requesting broad permissions
WHAT TO BACK UP
Everything that matters, elsewhere.
WHAT TO DO BEFORE DISPOSAL
Wipe it properly. Deleting files does not remove them.
WHAT TO CHECK PERIODICALLY
What is installed, and whether you still use it.