Shooting through glass window. In order to obtain a more artistic look, you may want to keep the light reflections. Simply secure the cameras on a tripod, set the timer for a few seconds, then take the shot. Be sure to move away from the object before taking the shot. The camera should also be covered with a black material.
On the other hand, if you need to avoid reflections, simply use “Polarized Filters”. They can help to capture light entering from the direction of the object while blocking those coming in from other directions.
Coloured Shiny Glass Products. In this particular case, you would definitely want to control the light reflections and not eliminate them. Compare the two vases below. Don't you think the vase on right looks dull and lacks the contour that we wish to highlight in this product?
Clear Heavy Glass & Crystal Glass. The same basic rule applies for shooting “clear” and “crystal” glasses. See sample below
Clear Thin Glass. You may wish to show only the contour, but should definitely consider leaving some shiny spots at the bottom of the vase.