Sienna Miller put this pastel/ombré hair color on our radar when she made waves at the 2013 British Fashion Awards. Her colorist's moniker for the color: "#pastelpeach." Ever the trendsetter, Miller's buzzed-about color is turning out to be the color for 2014.

Who Can Pull It Off: Petroff suggests trying a rose gold hair color if your skin and natural hair color already have similar shades. Paler skin tones, pinkish complexions and hair color that already has some natural red tone to it will easily transition.

What to Ask For: Whenever you're making a hair color change, set up a consultation at the salon first. You may think you know what looks best with your skin tone or hair color, but input from a pro may help steer you in another direction. Plus, the words 'rose gold' mean something different to everyone. Make sure you're on the same page by bringing in a picture of the exact hue you're after.

Beware Of: There aren't really any at-home products you can use to keep your pastel color looking fresh, unlike platinum hair's BFF, violet shampoo. If you're going to go for it, make sure you have a hairstylist you enjoy and can afford to see multiple times a month.

Kelly Osbourne knew the power of lavender hair color way before the rest of us, but we've officially jumped on the bandwagon. And so did Nicole Richie. She debuted newly pastel locks on March 3, sending Instagram followers into an instafrenzy. (And now, Lauren Conrad's joined the purple team.) But it's not just lavender that's in for 2014; Petroff and de Souza agree that any shade of pastel will make waves. So if you're dreaming of springy mint greens, cotton candy pinks or pale blues -- think beyond your wardrobe.

Who Can Pull It Off: You can. You just have to decide to commit and go with it.

What to Ask For: Ask if your stylist has done a hair color like this before you even make the appointment. Just because it's trendy, doesn't mean every stylist has tried it, and you want to be comfortable knowing you're not a test subject. If you have black or brunette hair, know you're going to have to bleach your hair. To avoid too much damage, Petroff suggests testing out the look on your just your tips.

Beware Of: Pastel shades can go from editorial to trashy in an instant. If you want to play around with soft shades, keep in mind you'll have to plan your clothes, makeup and hairstyle accordingly. Make sure to adjust your makeup so you're not washed out. According to Petroff, "Uggs and sweats just won't cut it."

Reasons I adore Cara D: her killer eyebrows, her complete lack of caring what others think and the fact she can pull off blonde hair color and dark roots without looking like she's in need of a trip to the hairdresser. Less maintenance and less money -- I'm sold.

Who Can Pull It Off: "This is yet another version of the popular ombré look," says Petroff. "It can be really great on people who have trouble pulling off fully blonde color. The darker top can help the dye job look more natural and subtle."

What to Ask For: If you are keeping your roots dark, restrict it to one or two inches and avoid going too light on the rest of your hair. The skunk look is not what you're going for.

Beware Of: This is a more extreme look, so it may affect your fashion and makeup choices. "Less aggressive clothes and makeup can create a really nice juxtaposition," says Petroff. Our take? If you have the confidence, you can pull off anything you want. Just like Cara D.

This season both Petroff and de Souza agree, there aren't very many color trends for brunettes if you're looking to stay in the brown family. However, various highlighting techniques are super trendy right now and can provide a subtle update to your hair color. For instance, the ombré trend isn't going anywhere soon, but 2014's sombré (subtle ombré) is the newest spin. Look to Mila Kunis and Olivia Wilde for textbook examples.

Who Can Pull It Off: Anyone can go brunette (spoken by a dark hair color devotee), but medium, olive skin tones pull off warm hues (caramels and auburns) best, without calling attention to any skin imperfections. If you have a cooler skin tone, choose cooler brunette shades (ashy colors, deep chocolate) for a more natural look.

What to Ask For: Rather than contrasting dark and light tones, de Souza says to ask for softer highlights that connect seamlessly from shade to shade. "Drastic shade changes more than two levels from your hair color are not the trend now. A shade and a half max for highlights."

Beware Of: Too often de Souza sees brunette clients who have gone too light in the name of "beachy." "Make sure the highlights blend softly or else the ends of your hair appear thin, or worse -- see-through,"he explains.

This French hair technique, whereby stylists freehand paint color onto the hair, can give you a dramatic or subtle ombré look, depending on your personal preferences. Take cues from Jessica Biel or Rachel Bilson.

Who Can Pull It Off: Literally anyone can pull off a stylish balayage color treatment, just be mindful of how much contrast and how much color you want.

What to Ask For: Be specific about what shades you want, how far apart you want them and where you'd like them placed. This season's trend favors more natural colors like caramel, rather than high-contrast blonde. Face-framing ribbons of color help brighten any complexion, Petroff says.

Beware Of: Consider the texture of your hair if you're thinking about doing a balayage color treatment. If you have finer hair, you'll want lighter, less chunky pieces of color. Thicker, curly hair needs larger sections of color to stand out, advises Petroff. But if you really want a high level of contrast, the balayage trend probably isn't for you. You should consider foil highlights.