Locate the nail bed, or quick, inside the dog's nail. The quick is easily visible in light-colored nails but can be difficult to see in dark nails. It is important not to cut to the quick, so cut small amounts. The cutting guard helps you move slowly and not over-cut.
If you accidentally do cut the quick, apply styptic powder to help stop the bleeding. After trimming the nails, smooth the sharp edges with a nail file or emery board.