How do I paint an accurate convex reflection with acrylic paint?

I am doing an painting, and in it there is a clock. To make it more accurate, I want to show a reflection in the glass surface of the clock, but I don't know the proper technique. I have two main problems:


How to make an accurate reflection - the surface is convex - and how to create the semi-transparent style that I need. I am using acrylic paint.How do I paint an accurate convex reflection with acrylic paint?
Well I just had this in painting class. You pick up the color of the reflection. It is very little white, but it is the colors it is reflecting. If you have a photo look more closely at it and see what colors the reflection is made up of. Some light gray might be needed. Practice on a paper before you add this to your composition.