Signs to look for in a girl that means she is very likely a bad choice as a wife --
* Manipulation, juggling several suitors, talking to lots of guys. A girl with more heart will see that, if she shows serious interest in one guy, she should concentrate on him alone. Then if that doesn't work, she can move to the next. Girls these days try to make themselves seem desireable by surrounding themselves with male attention, to stir up envy; this should have the opposite effect by repulsing good men.
* An excessive fascination with the media. I would say anything less than total contempt is an excessive fascination, by the way, and no, I'm not kidding. Now, she may turn on the TV from time to time, but overall she should be very aware of how evil it is. Many, many trad Catholic girls are way too into pop culture, and it warps their minds in a way that is all too apparent.
* A surly and sarcastic attitude, a general atmosphere of unhappiness, this is a sign the girl is not resigned to the will of God. She isn't content because she feels like deserves something more than what she has, she has expectations that are making her unhappy -- beware! A good wife rolls with the punches and accepts what God sends her. Very minor signs can tell you a LOT. With Catholics, you likely won't see any major acting-out, but the self-obsession will come out in subtle ways.
* If the girl comes after you instead of vice versa. Girls should wait until they are approached or get an introduction.
I believe that a relationship leading to marriage, if it is in God's will, will most often be smooth and easy. Two people like each other and figure it's about time to get married so they do it. They don't expect perfection but they see that they can make it work and they are compatible. There certainly is no room for any overt manipulation or game-playing with Catholic courtship.