Keeping your computer virus free and secured from unauthorized users

1) Use a good licensed antivirus.
2) Scan every external disk you connect(pen-drive,portables,phones etc)
3) Scan your primary drive every day if you are a regular internet user
4) Do not open any files from internet until it is scanned.
5) Install Operating System Security Updates
6) Install Application Security Updates
7) Keep your Antivirus Software updated
8) Install a quality Anti-Spyware/Malware application
9) Don’t be an Internet Victim. There are many phishing mails asking for your password and personal details.
10) Create a unique, strong password for each of your online accounts

Will update more points. :)

Any more points which could be added ? comment and i will add to the list.