I need to find an effective way to explain to people what sites to avoid and how to avoid them... I've become pretty adept (though not perfect, I will admit) at avoiding viruses and such that stem from fishy websites. I can even navigate through "warez" and crack/serial websites without getting infected at all. If I could explain what things to look out for easily and effectively, I could likely help a lot of people out :/
Hint: If it isn't one of the trusted names (AVG, Bullguard, Norton, etc.) do NOT install it.
Hint #2: If it advertises via popups, websites that pretend to "scan" your computer (usually by cheesy GIF animated images) or tries to trick you in any way, do NOT install it.
Also: if you don't already do it, before clicking a link you think might for any reason take you to a site you don't want to go to, mouse over the link and check the destination (if you don't already do that). In many cases that can give you a decent idea of where the link leads.