Clues you can use
Do you remember the time she gushed over a friend's engagement ring? (That was a hint.) And those magazine ads of diamond rings you found among your pile of papers? (Nope, that wasn't her being less tidy than usual—another hint.)
What's her style?
Does she wear a lot of sleek, minimalist pieces? Then consider buying her a modern channel-set ring with diamonds or gems (using her birthstone adds a personal touch). If she favors antique lockets and jewel-encrusted pendants she may love the romantic look of a pavé-set ring.
Your budget versus her fantasy
It's a fact of life that most women probably wouldn't be disappointed with a bigger diamond than they expected. More realistic per haps are the financial realities preventing you from buying the ring of her dreams. Read up on tricks for saving money on your ring purchase without sacrificing style—and even size!—in the Savvy Shopper section of this guide.
Do your homework
Studying up on engagement rings is the only way to guarantee an A-plus grade. Find out about the four C's, the different diamond shapes and ring settings and the hottest trends in ring styles. And if you can trust them not to spill the beans, her mother, best friend or sibling may be able to provide valuable insight into the ring she has her heart set on.
Consider her lifestyle
Does your girlfriend play sports, love the outdoors or enjoy arts and crafts? If so, then shop for a ring that suits her active life. A bezel-set diamond that won't easily snag or break loose is one great option. And channel-set diamonds or gemstones that sit flush on the band will give her just as much sparkle as that prong-set stunner!
Does she like surprises?
Only you can answer this question. But if you'd rather get it right the first time or know that she has very particular tastes, go ahead and ask her what type of ring she'd like or even go shopping together-both acceptable routes to take if you've already discussed marriage.
The placeholder ring
This is for the guy who doesn't want to propose empty-handed but hasn't been able (for any number of reasons) to get his hands on her dream ring. The placeholder ring can be a family heirloom, a piece of costume jewelry or a ring from a jeweler that she can later swap for one she selects herself. Many times jewelers will apply a credit toward the price of the new ring.
Get her ring size
Take note of the rings she wears on her ring finger, then when she removes one, slip it on your finger and mark where it stops on your finger. You can also trace the inside of the ring on a piece of paper to show a jeweler, though this method is a little less precise. If these tactics prove impossible, ask her friends to assist in getting her size by having her try on rings during a shopping trip.
The family stone
If there's a ring in your family or in hers, proposing with it is a sweet gesture. You can offer her the ring in its original mounting or reset the diamond in a more modern one so she can call it her own while at the same time honoring the original wearer's marriage.
Give yourself time
Visit jewelers at least eight weeks prior to popping the question. This leaves you plenty of time to purchase the ring and have it shipped. If you are thinking about engraving the band, keep in mind this can take up to a month, though in some cases as little as one week.
What's the return policy?
Things happen: The best efforts are met with disappointment (though if you follow these guidelines, it's highly unlikely you'll select a ring she won't love), and there's always the slight possibility that her answer isn't the one you were hoping to receive. To cover your bases, ask the jeweler about the return policy before buying the ring.
Ready to pop the question? See our groom's guide to planning the perfect proposal.