I think you have to be in tune with what the first move might be. It isn't necessarily going to mean that your partner is tripping all over herself to get into your pants. Most encounters aren't like in the movies, where two people start practically undressing each other in the hallway and stumble into the apartment before doing it pressed up against the wall. Real life is often much more subtle. Body language is everything. Such things as eye contact, taking your hand, leaning in for the kiss, flirting, putting her arm around you, are all signs that she is interested. In what? That remains to be seen. And how you respond to her may determine whether or not she feels comfortable growing more and more bold.
You also have to remember that many women (not all, but many) are raised with a somewhat traditional view point on sex and relationships. This means that the man takes more initiative than the woman because that is considered "proper" and it's just the way things are done. Do I agree with that notion? No. But it is what it is. And if you are dating "respectable" girls, they may be waiting for you to make the first move because on a traditional level, that's what's expected.
Bottom line is, sex should not be a waiting game or a battle of wills. If you're ready to move forward, give signals of your own. In the end, does it really matter who makes the first move as long as you both get where you want to go?
Best of luck.