The best tip I know to give is to watch the person you are interested in and see if they do what they say they're going to do. That's the best indicator of whether or not someone is going to make a good partner. Being single again, you don't want to get in a relationship like your previous one, do you?
I know, easy to say and hard to do, so I'll give another tip. Make sure you don't make up a person and project that illusion on a real person. From a guys perspective we do this all the time with girls when we're in high school. We see a pretty girl and think we know her and there's a connection or something. We already know what music they like, movies they watch, hobbies, etc. Which may or may not have anything to do with reality. So be careful that you're not projecting your wishes and desires on someone else, especially if they're the type to not keep their word.