I would like to make a blue glass shader in cycles. Something like this:
This was my first trying but I think it's terrible.
And here's my second trying but it doesn't look well.
Is there any way to make a shader like on the first image?
Try to mix two Glass Shaders- one with a white color and the other with a blueish color. Set the mix factor to a low value to make glass look more blueish and transparent at the same time. With a good lighting setup you'll achieve the effect you want.