You've probably heard of Josh Harris, the author of the book, I Kissed Dating Goodbye.
He's also the older brother of the twins, Alex and Brett, who wrote Do Hard Things, which I wrote a review about in the past. I recommend his book, I Kissed Dating Goodbye, as well as the sequel, boy meets girl. (yes, its title is not capitalized for some reason) The first book deals primarily with the subject of casual dating and why it's not a good idea, and the second deals with courtship. To put it simply, "Here's what not to do, and here's what to do."
Like I said earlier in this post, I recommend both books to any Christian who's not married yet. Even if you take issue with the books, read them and tell me what you disagree with. One single guy who goes to my church told me what he disliked about both books and even though we didn't agree on everything, I could mostly see where he was coming from, and we had an interesting conversation.
The second book is good reading even if you don't foresee getting married in the very near future, but particularly if you think you've found the "right one" and want some advice on what you should do while in the courtship stage to both glorify God and protect the other person. One thing Josh Harris says in boy meets girl that I find pretty significant is that if a courtship ends with both people not getting married to each other, it was not a failure. This is because a courtship is a time for a man and woman to see if they might be compatible and the right ones for each other.
Courtship is obviously different than casual dating, which just has pleasure for the moment in mind; while there is a bit more to it than this, it's basically just trying to get to know a person better to see if they're the one you want to marry (note that while there's always the possibility that the courtship may be broken off, marriage is the end in mind).