If You would have to do it on a showpiece, it would be quite time-consuming, using a mixture of veeeery smooth blendings and harsh reflexes in exactly the right spots. Taking a photo of a similar object under the lighting conditions You want to simulate might help. I think to reverse the highlights from where the liquid 'begins' is the key to success!
I tried this to 'gamig standard' once, converting a trumpet into a bottle. The highlights are done very smoothly, with the darker parts fading upwards into the lighter ones.The liquid is a lighter shade of the coulour used on the bottle, getting lighter towards the bottom. A few heavy gloss coats finished it.

I know a green bottle is not what You asked for, but if I would paint a clear glass, i would use the same technique of placing highlights and shadows.
Hope that helped.