I love the Cloud Nine phase when that guy from Biology asks you out and you spend hours figuring out what you'll wear and worry about what to say and how to act and you feel sick to your stomach. The first few dates can make you so nervous you want to throw up yet at the same time you can't wait until the doorbell rings and he opens your car door. You see him and he looks great and smells great and all of a sudden you forget everything you planned on saying and take it a moment at a time. Since you lose your mind as soon as you see Biology boy, you need to pick your outfit and look before you open that door!
Whenever I go out on a first date and it's nothing too fancy I always want to look amazing, but I don't want it to look like I tried hard. When you dress for romance, at least initially, the goal is to make yourself look great without looking easy. Especially on dates where you're not sure how you feel or it's a "just friends" kind of thing, look casual but cute. Most of my first date outfits consist of jeans that make my lower half look good and a figure-flattering top—look casual but pretty.
After a relationship is already underway dressing for romance is much easier because you've already got the guy! Now dressing comes down more to what you're doing as opposed to the reasons you wear what you wear on the first few dates. You still want to look good and attractive, but it's also okay to dress for comfort. After you've been on a few dates and he calls and asks you over to watch a movie, it's okay to wear jeans and flip flops. There should come a point when it shouldn't matter as much, when you don't have to work at impressing. (However there's nothing wrong with wanting to look good for your guy all the time!)
Something I've realized is that what's most important is not what my date thinks, but rather how I feel. If I like what I'm wearing then it's okay and it doesn't really matter what you do when you're out as long as you feel good. Romance is about love and passion and excitement, but it has more to do with being comfortable with yourself and yourself with that one person. In the scope of things, clothing honestly isn't as important as the other things that happen in romance. Clothing initially may contribute to the magic, and that initial magic is crucial, but remember that it's not what makes romance happen!