If the glass of your light bulb broke in the socket of the lamp, be safe! Turn off the power. Wearing gloves, preferably rubber, now, using half of a raw potato, push gently down into the broken bulb with the cut side down. The spud should be soft enough to grab onto the bulb yet firm enough to allow you to unscrew it and remove safely. Make sure you wipe the socket dry before adding a new bulb and restoring power.