These are the same two glasses as in the first photo, but with a green plate behind them. As with the orange background, the 'color' of the glasses changes significantly. Even the color of the liquid in the rear glass is different.
For me glasses are a good example of why, if you're wanting to paint in a realistic style, you should paint from observation, not your imagination. You are simply unlikely get enough of it 'right', to have all the small details that will make it real. It's hard enough overriding your brain's autopilot instincts with the objects in front of you!
Start by setting up the glasses so they're in a consistent light (not one that changes; a lamp may be helpful) and take the time to look at them before you start to paint. When you think you're ready, mix three tones -- a light, medium, and dark. (These can be any color, it's the tone that's important.)
Now do quick tonal painting or study with just these. You're not trying to create a finished painting, just a rough sketch putting down the shapes or areas you see as light, medium, and dark, in tone. (If you're using watercolor, consider using masking fluid to preserve the lightest tones.)
When you're done, step back so you can see both your tonal study and the glasses. Spend some time comparing the two, then adjust and refine your tonal sketch as necessary.