Step 1: To start with you need to decided how you want to shape your nails. I personally am not a fan of the pointed and oval looks. The pointed because it doesn't appeal to me and the oval because on my nails I think it would be too weak. Currently I like the square look, slightly rounding the very ends of my nails. I love this look on my short nails but find that when they get longer my nails look huge! Apparently your nails are stronger if they are shaped square or squoval and that has been my experience so far.
Step 2: Some people prefer to paint their nails, usually a dark colour, before they file their nails because they can see if they are getting a straight line or not. I personally prefer my nails to be bare so I can easily ensure that they are all the same length.
Step 3: My number on rule when shaping my nails is never, ever, under any circumstances use nail clippers! Before I would use them all the time and my nails constantly use to flake off and they peeled in many different layer and then became even weaker and broke. It was beyond frustrating! I use to think that perhaps if the used the nail clippers higher up on my nails and then used a nail file the remained of the way that I would stop the clippers from "shattering" my nails. But that didn't work either. Seems no matter how high up you clip the strength of the clippers really shears you nails for quite a distance.
Step 4: Now I know that you aren't suppose to file your nails back and forth as apparently it weakens them. But I have to admit to doing this on occasion when my nails have grown really long and I want them shorter and. Since I don't use nail clippers it would take me ages to get them down to size if I didn't do this. So I file down until I'm almost at the length I want them to be. I have read that it is best to use a glass file when shaping your nails and can tell you from experience that it is true NOT to use a metal file. Argh horrible flashback! I use a crystal glass file.
Step 5: Once your nails are near the length that you want them to be file them in one direction towards the centre or your nail. So file from the left to the centre and from the right of your nail to the centre. When doing this use the groove on the side of your nail as a guide. Continue to do this until your nails are the shape you wish.
Step 6: I usually run the file at an angle across the tip of my nail and then again under my nail to help dislodge any remaining sharp sections of nail and then again file from the side to the centre until everything is smooth. You can also use a buffer to smooth any harder edges you may have after shaping your nail.
And that's all there is to it! My nails grow very fast and I usually reshape them after about a week and a half. since everyone is different you might not have to shape your nails as frequently. However, after shaping your nails a few times it should become second nature to you!