Whether your fingernails are long or short, strong or weak, they are still made out of the same thing. Our fingernails are basically made up of a hard, curved plate of keratin. Keratin is a protein that is also a main ingredient of hair and skin. At the base of a nail is what is called the matrix (and no, we are not talking about the movie). The matrix is where the nail forms from; this is what most people call 'the moon' of the nail. This 'moon' appearance is due to the nail bed being so tightly packed with keratin, that the capillaries (where the blood flows through) is masked by the amount of keratin. The rest of the nail that is actually attached to the skin appears pink due to the capillaries running underneath (the blood running through them gives them the pink colour). And of course if you are lucky enough to have longish nails, then the ends (called the free edge of the nail) are usually white in colour, as there is no pigment in the nail to give it colour.
Now that you know a little about the anatomy of the nail, I will begin to tell you some helpful ways to look after them.
Keep them moisturised
We use our nails all the time, but it's when they are in water, that they get the most damage. This is due to a specific type of cell in the nail bed of keratin which acts like an adhesive, holding the keratin closely together to give the nail it's hardness. However, if the nail receives repetitive soaking in water, or contact with soaps, dishwashing detergents, and household cleaners etc. it will damage these adhesive cells. So in order to combat this problem use a good moisturiser - one that absorbs really well. Rub it in as often as you can, especially when you come into contact with water and other abrasive products. If you already suffer from brittle nails, this is a must, if you want to protect what you already have, even if it's not much (but it is a start). What you want to achieve is a seal on the surface, and on the ends of your nails, along with soft, but firm cuticles. This will also prevent dehydration of the skin on your hands, and lessen the chances of dry, cracking nails, along with dry nail beds.
Things that cause cracks & splits
Doing normal things with your nails such as picking things up, drumming them whilst thinking, scratching your itches cause cracks and splits. There are other things that cause slight trauma to the nails, and these do build up and cause nail damage.
Picking at your nails. This obviously weakens the nails, as it tends to crack or peel the top layer off the free end of the nail. So lets try not to do that one, if you find you do this under stressful times, buy a stress ball, these are also lots of fun and feel good.
Biting your nails. Well you couldn't get a more damaging habit (well maybe dipping your fingers in some kind of acid!), so I'm sure if you are a nail-biter you are already aware that this habit is destroying your nails. Again, try something like a stress ball. Or try the simple trick of placing a rubber band on your wrist, and every time you find yourself nibbling 'flick yourself'. After a while you will find this pain rather annoying, and may reduce that biting. You can also try that horrible tasting stuff that you can put on the end of you fingernails, so that every time you go to bite, you taste this bitter stuff, which is meant to be a great nail biting or nail chewing deterrent.
Picking off nail polish. Now this habit one of my favourite pasts times, I drive my friends crazy with my half chipped nail polish, while they beg me politely to just remove it with nail polish remover. But I even more politely insist that I enjoy picking it off (I guess it's my equivalent of nail biting). This is not good for your nails; it will only weaken the outer layer of the nail and peel or split the free nail.
How to improve your nails
Cut your nails after bathing. If your nails are dry and brittle, cutting them when you nails are dry can cause further cracking. So when it's time for a cut, do it when your nails are soft from bathing.
Carry an emery board with you. This is so any potential cracks can be smoothed out, preventing further damage to the nail, and reducing snapping.
If you have fragile nails, the best thing to do is to keep them short. This reduces damage, as the longer your nails are, the more they stick out and the more they are at risk of cracking and splitting.
Don't push your cuticles back, they are there to protect your nails for a reason, pushing them back can impair the health of your nails. It can also leave the base of the nail open to a potential infection.
Reduce the amount of nail polish remover used. If there is a chip, touch it up with more nail polish, rather than removing it from the whole nail. Try to keep the use of using nail polish remover down to once a week, as it is just really bad for your nails, causing them to dry and potentially split.
Keep your nails curved at the top if you like, but don't cut the edges into a curve. Squaring them at the corners will help to provide strength, along with helping to avoid the chances of an ingrown nail.
Some interesting facts about nails
Nails grow at the rate of 0.1mm per day
If you are right handed your nails will grow faster than your left hand. If you are left-handed your nails will grow faster on your left hand than your right.
Your nails can reflect the state of your health.
Light trauma such as piano playing or typing on a computer keyboard can actually stimulate the growth of your nails.