File, DON'T cut!

Using a GLASS file on your nails won't damage them like a nail clipper can. I will say, I do use a clipper if I'm cutting my nails drastically shorter, but I will cut them longer than I want them so I can avoid nail peeling.

NEVER file back and forth, ALWAYS go in one direction. I tend to do the left side of my nail going to left, and the right to the right. Going back and forth can cause too much friction on the nail causing it to break or peel.

I also wouldn't suggest using an emery board, those can be way too rough on the nail.

An example of what a glass file looks like.