Ricardus touched on avoiding STDs a little in "Dodging the Dangers of Sex (and Dating)", though his focus there was more on some of the other dangers that can arise; and I have a post on the forums that covers a good chunk of what we'll talk about in this article here: "Re: The Dangers of Sex." However, I wanted to clean that information up and put it in a more presentable (and scannable) way - hence, this post.
When you're relatively inexperienced with women, it's easy to get freaked out about STDs. Typically, the more sexually experienced you get, the less of a "big deal" these seem like... and, generally, the more likely you are to run into them.
Yet, if you're smart, and you do your homework, it is possible to avoid STDs almost entirely, even while having lots of sex with lots of partners... BUT, you must do your homework, and you must be on top of the ball at all times, because if you're trusting your own sexual health will be looked out for by that pretty stranger you just met (after all, she seems so innocent...), you've got another thing coming.