There is something that bothers me on your render. This is like if there were no perspective. Have you did your render in an orthographic view ? Or your modeling is a bit twisted (window, table, monitor or ground).
However for some elements, beware of your smoothing groups and proportions, especially your monitor, on the left side, some polygons aren't smoothed and it is too big compared to the keyboard, or too small compared to the window.
And finally, I advise you to work more on your lighting. Harsh shadows tend to overwrite your scene.