I’ve just spent 5 minutes on your file - I know the tut which you followed. I understand you just wanted to try out the scene, so I won’t go too much into the modelling
Avoid using the solidify modifier if you can. Try to re-model the jug for example, or just a simple bowl to start with. Create the inside manually by extruding, when you get to the centre - Press ‘W’ (Specials menu) > Merge>At Centre. Try to keep the topology the same as the outside so that the curve follows it’s shape. Don’t make it too thick, generally glass objects don’t have too much thickness.
On the top edge of bowl/jug etc, create some loop-cuts to tighten up the edges (CTRL+R) - slide them to the edges and leave a little gap.
Next the IOR for the material should be 1.45 there abouts for the default glass.
The scene itself is pretty much all white and nothing in it to reflect - glass never looks good like this.
Try rendering the scene without the sky-texture and the box/room - change the background colour to black and just use a couple of light emitting planes instead, you’ll see a huge difference.
you’ll see in my blendswap files, I usually use a curved L shaped backdrop, this is a handy way to learn the way lighting works in cycles and can give great results without too much effort.
To finish, I’m not sure why the solidify modifier can cause so much trouble, If you do use it, use ‘Even thickness’ and ‘High qualit normals’. I did try re-calculating the normals (CTRL+N) and even flipped the normals, but the issue still remained till I removed the inside - which is what the modifier had created.
Hope that helps, sorry for the length