Style:

First off, trust yourself! Putting all of your faith in a ring that will be part of your life forever is bound to be a stressful decision. When browsing ring styles, ask yourself if you'll be comfortable wearing it every day for the rest of your life. A traditional plain gold band will be in style for many years. Is that too plain? If so, think about a beaded edge or an engraved style. Looking for some more 'bling'? Consider a ring of channel-set diamonds. Most importantly though, choose a ring that fits your style, your personality, and your heart. There is no wrong choice on style. As long as it is genuinly you, you can't go wrong.

You don't need to feel forced to choose the same metal as your engagement ring. Many couples choose to do this, but you certaintly do not need to be bound to this. As a bride, you can choose to wear your wedding ring on your left hand, and your engagement ring on the right hand. Also, both the bride and the groom can wear a similar style in different metals. Which metals do you wear regularly? Is her jewelry gold ? Is his watch silver? This can be considered also.

Primary ring metal choices include:

Yellow gold:
the ring metal that is most traditional; for many gold is a symbol of the warmth and love of a marriage. Look at the mark inside the band to see what quality the gold is - usually 14k, 18k, or 24k. While 24k is the most pure, it is also the softest. If you work with your hands, you may want to choose 14k or 18k to prevent scratches.

White Gold:
A hot trend because it coordinates with both silver and platinum jewelry, yet is cheaper than platinum.

Platinum:
This very stylish metal is also the hardest metal, making it for many a symbol of enduring love. Also, because its not mixed with the lesser metals that gold rings are, platinum is safe for those with alloys. However, you'll pay more for platinum than for gold.

Precious Gems:

Softer stones can be beautiful, but they aren't the best choices for an engagement or wedding ring. The Mohs scale registers a stone's ability to resist abrasion with 10 (such as diamonds) being the strongest and 1 (such as talc) being the weakest. Ideally, you want something higher than an Mohs of 7 for an engagement ring. If you work with your hands a lot, then consider limiting your selection to rubies, sapphires and diamonds. Also, remember that the darker the stone, the more expensive.

Diamonds:

Remember the 4 c's: color, cut, clarity, and caret.

Colour - With the exception of some diamonds, the more colorless a diamond is, the more valuable it is. Jewelers grade diamonds on a scale from D (colorless) to Z (light yellow). Anything more yellow than D is higher saught after, and is more expensive.

Cut - Cut means the way the diamond was faceted to allow light to reflect from it. In a well cut diamond, light enters the diamond and reflects straight back to the viewer's eye. Some cutters will sacrifice cut to create the largest possible diamond, thus making too shallow or too deep of a cut and causing light to "leak" out the sides and bottom of the diamond. Get an AGS Certificate or a GIA Certificate verifying the quality of your diamond. Cut is graded Ideal, Premium, Very Good, Good, Fair, and Poor. Generally you should seek an Ideal to Very Good Diamond. Budget-conscious shoppers may opt for good.

Clarity - Diamonds frequently have inclusions, or small flaws, air bubbles, scratches, or other minerals inside the diamond. The less inclusions a diamond has, the more valuable it is, and the more beautiful it is. A diamons clarity are usually scaled as: F (Flawless), IF (Internally Flawless), VVS1-VVS2 (Very Very Slightly Included), VS1-VS2 (Very Slightly Included), SI1-SI2 (Slightly Included), I1-I3 (Included).
Stones that are VVS2 to F are very rare and thus very expensive. Most couples will opt for something between SI2 and VS1, and will never know the difference.

Caret - This refers to the size of the stone. While some value caret above all, others prefer a small ring regardless of budget. If you're buying a ring as a surprise for someone, consider how flashy their other jewelry is. If they're not someone who wears a lot of designer labels or big jewelry, perhaps you'll want to opt for a smaller stone. This site has a very useful chart to see how the most common sizes look on a model's hand. Ideally, you'll be able to try on a variety of sizes within your budget to see which size looks best on you or your love.