Trim your nails regularly.
Use manicure clippers and trim your nails straight across. It’s easier to trim or file your nails after a bath or shower since your nails are soft and more gentle to clip.
Use hand lotion.
When using moisturizer, you soften your hands and your fingernails and cuticles become soft and stronger and make them healthier looking and makes your skin soft too.
Keep them hydrated.
Rub a penny size amount of petroleum jelly on your cuticle and the skin around your nails every night before you go to bed or when your nails are dry. You can also use castor oil which is think and has a lot of vitamin E in it and is healthy for your cuticles.
Dip your nails in olive oil.
Dip your nails in olive oil each night for 2-3 minutes only. This makes your nails stronger and healthier looking and protects them. Don’t do this more then 5 minutes a day this can ruin your nails if overdone.
Keep your nails dry and clean.
This will prevent all of the bacteria, fungus, and other germs from developing under any of your nails. You should always wear cotton-lined rubber gloves when cleaning around the house or using chemicals.
Trim toenails straight- When trimming or clipping your toenails, trim them straight across to prevent ingrown toenails, which can be very painful.
Avoid types of removers.
When removing nail polish, try avoiding removers with acetone or formaldehyde. They dry your nails out completely leaving them with no hydration and makes them weak. Try using acetate-based removers instead, when buying removers.
Using biotin 4-6 times a day makes your nails as strong as a horse’s hooves. Biotin strengthened horses’ hooves, which are made up of keratin, the substance in a human’s nail. Researchers found out that people who used biotin had firmer, harder nails.
Massage your nails.
This will keep them strong. Buffer nails increases blood supply to the nails, which helps the nail grow.
Don’t share a nail file.
Using your friend’s nail filer is a big no no. It contains germs, and bacteria in them from the persons own nails that catches them. Keep them to yourself and replace after 2 months.source: http://www.wikihow.com