Careful. You can’t screw this up. She’ll repeat this story again…and again…and again…for the next two years. So follow the 10 Commandments.

You know the “Reset” button? When you’re playing “Grand Theft Auto” and you get pistol-whipped, you can just hit Reset, start a few levels back, and then resume killing cabbies.

Most of your engagement has a Reset button. Not the proposal. You can’t undo it. The stakes couldn’t be higher. Assuming she accepts, she’ll describe every detail-from the salad dressing to the roses to the way your voice quivered-again and again to everyone she has ever met. She’ll blog it. Facebook it. Twitter it.

In some ways, the proposal is bigger than the wedding itself. No pressure, but your life hangs in the balance. Follow the 10 Commandments of Popping the Question:

1. You shouldn’t be surprised …

Like a good lawyer, don’t ask the question unless you know the answer. And if you don’t know the answer, consider whether you’ve given your courtship enough time. (Hint: you haven’t.)

2. …but she should.

You must surprise her. That’s the game. If you talked about getting married last week, then when you say, “Hey. Um. I was thinking… maybe we could go on a hot-air balloon ride together. My buddies were saying it’s fun,” there’s a decent chance that she’ll crack your code. Keep your cards close to your chest. Don’t tell too many friends. Lie.

3. Only go public if it’s a lock.

If there’s any uncertainty, popping the question in front of 16,000 Yankees fans could either: 1) be the most humiliating moment of your life; or 2) force her to croak out a “yes” that she (and you) will later regret. In any event, think very, very hard before making a public proposal. Unless it’s a Royals, Indians or A’s game, where the 134 fans won’t care.

4. Personalize.

This helps you dodge cliches. As much as you might be tempted to go to “www.800uniqueproposalideas.com,” there is nothing unique about them. You already know everything you need for a memorable proposal. Think about her interests and then tailor your proposal accordingly. It shows that you actually know her, love her, get her. If she’s a tree-hugging outdoors freak, then incorporate a hike, camping trip or hide it in her bowl of granola. (Kidding on the granola, which brings us to…)

5. Guard the ring like it’s Your Precious.

No brainer, right? But it’s shocking how many guys hatch some bold, creative plan that ends up with the ring lost in garbage. Plan nothing that risks the rock. Don’t bury it on a beach. I don’t care how much she loves “The Claw,” don’t toss it in the machine and have her try and get it out. There’s a fine line between creativity and stupidity. Don’t go near that line.

6. Take a knee.

Corny? Maybe a little. But by taking a knee, you fulfill the vision that she’s had since she was a very little non-ironic girl. Also, her girlfriends will specifically ask her whether you got down on a knee. Let her answer the right way.

7. Keep heavy eye contact.

It shows you mean it. It shows confidence. Lock onto her eyes and never glance away. Just like in poker, a nervous glance to the side is a “tell” that could lose you the hand. (To clarify: blinking won’t cost you the “yes,” but why take chances?)

8. Actually have a ring.

Remember Lumbergh from “Office Space”? I had a boss like him. Even though my boss made good money and could easily afford a ring, he didn’t feel like waiting for the jeweler, so he popped the question sans diamond. His strategy? He printed out a picture of a generic wedding ring – in black and white, even – and scribbled “I.O.U.” on the paper. Yeeeeaaaaaahh. Don’t be Lumbergh. Bring the loot.

9. Practice.

We can almost hear Allen Iverson: “Practice? Practice?!? We talkin’ about practice!?!?!” Yes. Practice. Rehearse your shtick in advance. Look in the mirror. Propose to your dog. Say it in the shower. It’s embarrassing and you’ll feel like a moron, but it’ll give you more confidence in the big moment.

10. The setting trumps size.

Ambiance is key. It’s better to have an outdoor, intimate, candlelit picnic than a lavish, $600 dinner at a “hot new restaurant” that blares hip-hop. It can be pricey or cheap, small or big, private or public, but the atmosphere must brim with romance. We’re often wary of the “cheese factor” and shy away from roses and their ilk. But not here.

Guess what? In a marriage, if you’re given 10 rules that really means you have (at least) 11. So here’s one more:

11. Relax.

We know. This seems like a paradox. But as long as you’ve thought this through – planned things to a T, ensured she’ll say yes, practiced in the shower – you’ll be fine. For real. Don’t worry about stuttering or sweating or flubbing the lines. Even if you stumble over your words and have pit-stains like Ted Striker from “Airplane,” don’t worry, she’ll find it endearing. That said, wear an undershirt.

AFTER “YES”

This is it. This is the one moment that belongs only to you and your future wife. Make it last. This is one of the most intimate memories that you will ever share with anyone, anytime, anywhere. This is the calm before the storm, the slice of tranquility before you make 200 calls to the family, friends and vendors. It’s the final truly quiet moment until your wedding. Savor it.

ONE NOTE ON TIMING …

Timing matters. The month of your proposal could impact the length of engagement. If you want a long engagement, for example, propose in the spring – there’s a good chance she can’t whip together a summer event, so presto, you’ve bought yourself more than a year. Conversely, if you propose in the winter, you could go down by the first day of spring.

For more on grooms, wedding planning, and relationships from the guy’s perspective, visit www.ThePlunge.com.