Ideally, physically or using a operating system which supports compartmentalization, therefore isolating it from your daily activities is the best approach. I'm an advocate for Qubes OS which not only isolates each qube from another i.e instances of a operating system, it can optionally isolate your network from them too. There's also options to have a disposable sys-net, which upon rebooting resets it back to the template, so if you did get compromised it would only be for that session.

Although, even without isolation techniques, you can avoid most problems by not downloading anything that you haven't verified to be legitimate.