The thing about wearing baubles, beads, and all sparkling things is, genuine materials or not, it's easy to end up looking overdone. When including costume jewelry in your style, the best way to avoid coming off cheap is to follow one simple rule: Less is more.
You can have the most beautiful costume ruby necklace and turn it into an imitation nightmare by adding a ruby ring, ruby bracelet, ruby earrings, two gold chains, a pearl choker and ruby-and-sapphire headband. Matchy-matchy is usually kind of tacky, and, as they say, how classy a woman looks is inversely proportional to the number of rings she wears.
Keep it simple. If you're wearing a particularly large piece of jewelry, treat it as a focal point. That means only one necklace, and perhaps one or two other "background" pieces, simple gold hoops or a few silver bangles, for instance. You can wear a larger number of subtle pieces at once without looking cheap, but even with simple jewelry it's wise to edit. A thin gold chain can look a bit street-walker when you pair it with 20 more just like it.
Aside from limiting your jewels to a few well-chosen pieces, looking expensive in the inexpensive can also come down to:
Size -- Unless you're royalty, you probably won't look classy in a lemon-size "diamond." Keep it small and tasteful.
Color -- If you're going for an expensive look, a hot-pink or lime-green stone can be tough to pull off. To be safe, stick with colors in the natural-stone spectrum.
Outfit -- Most people look cheap pairing a 10-carat "ruby" with sweats and a t-shirt. Sure, a lucky few in Beverly Hills can make it work, but most people do well wearing fancy jewelry with evening wear and casual jewelry with jeans.
One other thing to think about when wearing affordable jewels: Some people have allergic reactions to certain inexpensive metals. Before you wear a costume piece for a night on the town, make sure you're not allergic to the chain or setting. No one looks expensive in a rash.
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