Your laptop comes with anti-virus software, often on a trial basis. Be sure to renew it or install new software when the trial period ends.
Enable the update notification function on your laptop. Don't ignore update notices, but definitely DO ignore security updates from email or website pop-ups. They could actually be viruses.
Use strong, frequently changed passwords to protect your device. If it's ever lost or stolen, your information will remain safe from whoever's hands it falls into.
When you download files from the Internet, make sure they're from a trusted source, and always use your anti-virus software to scan the files you download.
Only use wireless networks and hotspots that you know – like your local coffee shop or somewhere they provide you with a password to use their Wi-Fi. And never conduct financial transactions on public Wi-Fi.