As mentioned previously, lighting is the key. Aside from that there are a couple of things you can do to reduce the amount of glare depending on what your purpose may be but it will never be completely eliminated.
If it's an issue while still working on the drawing you could try a 'workable fixative' with a matte finish to help reduce the glare. This comes in a spray can that you can get at any art supply store and it's relatively inexpensive. Being that it is "workable" means that you can continue to work on your drawing even while it has a fixative on it (this will also help with smudging and with getting graphite on the back of other pages in a book). When the drawing is done spray it with a matte finish and that can help as well.
I was also imagining another scenario if the art is being shown in a gallery and you don't have control of the lighting. Matte and frame your artwork with low glare glass. It's a bit more expensive but it'll make your artwork look classy and ready for a big sale. The low glare glass is usually UV resistant to archival quality so you don't have to worry about your substrate becoming discolored over time. Let us know if you find a solution that works for your art.