What I really love about this graphic stuff is making something from nothing and it turns out looking realistic.
After many years I'm still searching for a tutorial on creating the ultimate in realistically looking 'glass'.
For the time being though, I really like playing around with effective shadowing and reflections.
I followed this fantastic tutorial
http://alfoart.com/vip_pass_1.html
yesterday and ended up with the pic below.
(The angle of the reflection is slightly off as its supposed to be leaning back a bit.)