For glare on the front of the lens (also known as lens flare), you need a lens hood. For your lens, it's the EW-78BII hood. A polarizer will help in certain situations to reduce glare/reflections from water, glass, and other reflective surfaces. It will also increase contrast in the sky, at its maximum when you're 90degrees perpendicular to the sun.
You can order any of these from www.bhphotovideo.com
, and many other places.