We've been working in class using colored pencils on toned paper to draw clear plastic bottles.
Here are my examples.
Can you guess what the bottle is on the left?
I didn't have time to finish it because the bell rang and the student wanted to take her drink.
Really? Didn't she know I was in the middle of a masterpiece?!
The water bottle is complete though. They are on a 9x12 piece of brown paper.