Gather up a high quality pair of trimmers and some styptic powder, such as Kwik-Stop  or other product, to stop bleeding if you nick the quick.
You may want to sit on the floor with your dog in your lap, or have someone hold your dog on a table. Hold your dog’s paw firmly and push on the pads to extend the nail. Locate where the quick ends. With clear or light nails, it is easy to see the pink color where the quick ends. But with black nails you can look for a black dot on the underneath of the nail; that’s where the quick ends.
Trim the nail below the quick on a 45- degree angle, with the cutting end of the nail clipper toward the end of the nail. Make several small nips with the clippers instead of one large one.
In some cases, if the nails are brittle, the cut may tend to splinter the nail. In these cases, file the nail in a sweeping motion starting from the back of the nail and following the curve to the tip.
Go slowly, take breaks between each paw., and don’t forget the dewclaws. If you accidentally cut the quick, wipe off the blood and apply Kwik-Stop or styptic powder to stop the bleeding. It is not serious and will heal in a very short time.
Some important tips: