Probably my best work for now. Just a beginner^^
Wow! This is really awesome! 
I love the depth of field effect, but the blured parts of the image is pixelated… 
Are the effect made in Blender or with gimp/photoshop??
Very good, you should try to add an HDRI image for the background, it’s not much work and you will have much nicer reflections! (Or maybe you did and then it’s the materials that need a little more work!)
Also it’s a shame that the black keys look like they intersect with the white ones!
But anyway, you’ve got the compositipon and lighting quite right, which is really essential! Congrats!