Whether you long to show off a colorful manicure, or merely want strong nails to scratch an itch, growing long, strong nails requires a combination of good habits and good health. Though some people grow long nails without much effort, other people have to work to produce manicure-worthy nails.Keep nails dryWater softens nails and can make them more brittle. Wear gardening gloves when performing yard work and slip on a pair of rubber gloves before washing dishes or scrubbing down the bathroom. Dry hands and nails thoroughly after bathing or swimming.Use tools, not nailsDon't use your nails to pry open pop-tops, pick the price tags off picture frames or scrape gum from the floor. Use the edge of a knife or a scraper made for the purpose. Adopting this habit will come in handy when you do succeed in growing longer nails, as these same practices will help keep your nail polish from chipping.Don't pickYour mother was right when she told you not to pick at your nails. Picking at your cuticles can damage them and inhibit nail growth. If your nails are chipped or peeling, picking at them will only weaken the nail further.FileKeep nail edges smooth by filing with an emery board. File in one direction only. Filing back and forth could make the nail edge more ragged. Ragged edges can catch on clothing and tear. Use sharp nail scissors to trim your nails.PolishA light coat of nail polish can help protect your nails, keeping them from drying out and protect nails that have a tendency to peel. Nail hardeners can also help strengthen your nails. Mayo Clinic.com advises avoiding any products that contain formaldehyde or tuluene sulfonamide, since these chemicals can irritate the skin.Polish removersAvoid using nail polish remover more than once a week. Mayo Clinic.com cautions against using polish removers that contain acetone, which dries nails. Look for formulas advertised as acetone free.MoisturizeRegular moisturizing helps keep cuticles from drying out and will promote nail health. Rub moisturizer into your nails after a bath or whenever they've been in water. If dryness is a real problem for you, Mayo Clinic.com suggests you rub moisturizer onto your nails before bed, then slip on a pair of cotton gloves and leave them on while you sleep.NutritionGood nutrition promotes overall health and nail health. In addition to eating a balanced diet, you could take biotin to promote nail growth. The University of Maryland Medical Center reports that biotin may help improve nail health.