Making a good first impression is vital during an interview, perhaps even more so when you're a teenager. You have to prove to your prospective employer that you're mature enough to be relied on and that you'll be an asset to his business. The first thing he'll notice is how you present yourself, so it's very important to be selective about what you wear.

Be Conservative

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The Quintessential Careers website recommends dressing conservatively, even more so than the dress code in the workplace. Don't assume you can show up in jeans and a hoodie just because the business is casual. Err on the side of safety. Ladies, keep the necklines modest, the jewelry at a minimum, the hemlines decent and the heels low. Gents, keep your pants belted at the waist and the shirts buttoned. Make sure your clothes are clean and pressed, and have an adult give you the once-over before you step out the door.

For Girls

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A nice blouse, knee-length skirt and closed-toe pumps with one- or two-inch heels is fine. You can swap the skirt out for a pair of slacks, if you like, and top it off with a professional blazer or cardigan. Avoid crazy colors or patterns, and anything that loudly touts a logo, recommends Teen Force.

No tassels or wildly glittery clothes. Stay away from clingy, revealing clothes, as well as anything too slouchy; strike a balance. Keep your makeup understated and subtle: a little mascara, blush and lip gloss are really all you need. The same goes for your nails: keep your polish simple.

For Guys

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Imagine what you'd wear on a Sunday at church. A nice pair of dress slacks, a button-up shirt and a tie are perfect. Don't make the mistake of choosing casual footwear. Stick to classic dress shoes and dress socks. Wearing a suit coat is up to you, says Teen Force; it isn't totally necessary unless the business you're applying with is highly professional, like a law office. Likewise, a vest may be a little too formal.

Don't Skip Hygiene

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Your clothes aren't the only aspects of your appearance the hiring manager will notice. Your overall presentation is equally important. Shower beforehand, and trim and clean your nails. Your hair should be clean, dry and styled nicely. Keep facial hair to a minimum; if you have a mustache or beard, make sure they're trim and tidy. If possible, cover tattoos either with your clothing or discreet makeup. Remove alternative jewelry like nose or tongue rings, advises Sharon Ann Holgate, a writer for Science Careers.