Glare, otherwise referred to as hot spots, are areas on an image that are caused by direct light shining off of a shiny surface and bouncing right back to the camera.
The same light can also produce dark photographs as well often times referred to as distracting shadows.
In many respects glare can be eliminated by moving the light source, or softening the overall light source that encompasses the image.
The overall solution to adamant glare problems largely depends on the overall shape of the object that you are wishing to capture.
In the respect of flat objects, the solution to your glare problem is as simple as moving the light source from the image. With objects that are angled or contain rounded surfaces, your best solution would be to soften the light. The reason for this is it doesn’t matter where the light is, it will consistently reflect back onto your camera.
Keep in mind that the term softening the light does not mean to simply reduce the light altogether. Turning down the lights that surround the image will not do anything for the glare, it will still be apparent in the photographs.
The only difference is the glare will reduce causing a smaller image of the object you are capturing. Softening the light simply means to change the light source from either direct or hard sources.
Bare lights or the sun are considered to be harder sources that can in most respects eliminate the light source. The standard way that many people opt to soften the light is to utilize a diffuser or simply bounce the light off of a larger surface.
For many objects the easiest way to eliminate glare is to utilize what is referred to as a light tent. Using a light tent, allows direct or hard light to be eliminated as it passes through the fabric. If all the light that is coming off of the object passes through this tent then the glare should be completely eliminated.
One of the most common causes of glare is shadows from an on camera flash source. If you are capturing an image that already gives off a shine with your flash on glare will be incredibly imminent in your photograph.
Unless, you have a special flash it would behoove you not to utilize the flash of your camera when capturing an image that illuminates a shine.