The biggest thing that singles ought understand about fights - IMHO - is that there are no bonus points/cookies to be given for staying in a bad relationship. If you are single - that means you have license to leave. Dating is not "marriage-lite", nor is engagement (really). You have no obligation to stay, and if you find yourself having lots of problems before you're even married, that should be a sign to go.
Unfortunately, as a society we've cultivated this belief that learning to stick with things, or work through things, is a worthwhile goal. While that's true a LOT of the time, it's not an absolute truth. The kind of stuff you should know how to work through is "hey, our point of view on what time bedtime for the kids ought be differs", or "our point of view on a subject differs". Yes, under those types of circumstances, absolutely, learn to talk things over and work things out.
But then you get crap like "he beats me", "we berate each other" or "she cheats on me". Sorry, but IMHO if you're just dating, it's high time to leave. Unfortunately though I see a lot of people that stick together like they're already married - and see it as some badge of honor that they worked things out. In a sense, it's like they're married again and again with all of the duties and obligations of marriage to a whole bunch of people, until finally one sticks.
Don't do that. That's what I think singles ought understand. lol