1) The beginning of a romance novel is a map of the whole book. It contains most of what you need to know to find your way through. These things include, but are not necessarily limited to:

• Why the heroine is your new best friend
• Why the hero is the man you want to spend your life with
• Why they're perfect for each other
• Why common sense requires them to stay away from each other
• What they think they're trying to accomplish

Or to put it more technically, in addition to introducing the hero and heroine, the beginning reveals the internal and external goals, motivations, and conflicts for both.2) You must write the beginning perfectly, twice. Once before you have written the book, because it is a map for how you will write the book, and one after you have written the book, because of course you can only map a territory once you know it intimately.3) Situation is everything. You must immediately dump your hero and heroine into the most character-revealing conflicts you can. Think of it this way. How will you know she is your new best friend if you don't see her in action in a tough situation? How will you know whether he's the man you want to spend your life with if he doesn't prove his mettle quickly (and sexily)?4) Make 'em suffer. See number 3. You must make their lives very difficult, very fast. As difficult as possible. So difficult that you would be royally pissed if the god of your own universe ever did that to you. Because if you don't get them pissed or hurt or scared or sad, and quickly, the reader will not care about them and she will stop reading. And then you will not have a chance to redeem them and do wonderful things for them and give them a happily ever after that will stick with your reader forever.5) Backstory is destiny. What has wounded your hero and heroine in the past determines how they will behave in the situation you dump them into and in every future situation they encounter. If there is something that has made this union inevitable, don't be cagey about it--tell the reader. On the other hand, a novel is all about what happens next, not what happened before. Integrate backstory subtly and smoothly and don't let it bog down the forward action.6) Settle in. Ruthie Knox gets full credit for this observation. The reader needs to get comfortable with the idea that she has just met her new best friend and lifelong mate. Don't give her whiplash by moving on too quickly. Spend time in these new, character-revealing situations.7) Don't start with the meet scene unless it's the right place to start. If your hero and heroine meet in a place and in a way that genuinely reveals who they both are, by all means start there. Beware, though, that this is more often the case when the hero and heroine are in conflict with each other than when their primary conflict is with other characters or outside situations.8 ) Notice only what your POV character has time to notice. The way to figure out how much description belongs at the beginning of the book is to figure out how much your POV character is capable of noticing. And what your POV character is capable of noticing. Everything you describe is seen through your POV character's personal filter. Don't think of description as capturing the physical world, think of it as capturing the POV's character's emotional reaction to the physical world.9) Only fresh readers know if your beginning works. A beginning works only if it works for someone who knows absolutely nothing--nothing--about your book and its world. You need to expose it to a fresh reader to know if it draws them in. And yes, I think it should be a regular reader of romance, because only they know whether you've succeeded according to romance-reader expectations.10) Beginnings have to be more and better than everything else. That's not just because you need to quickly impress agents and editors, although that's another good reason to make your beginning more and better (though not at the risk of neglecting the rest of the book). It's also because of the nature of beginnings. When you know absolutely nothing about a person, or two people, or a situation, your brain requires that much more information, that much more skillfully delivered, to make sense out of it. Once I know what a certain setting looks like, you don't have to tell me again. Once I know the heroine is quick to anger and quick to forgive, I'll take a certain amount of temper for granted. But at the beginning, I know nothing. Your descriptions have to be better. Your characters have to be rounder and realer. And any back story you give me has to tell me everything I need to know--quickly and efficiently--without messing around. More. Better.