From the Painting Guide: I don't think this is too busy at all; it's got an atmosphere reminiscent of some of those Impressionist paintings of drinking-hall scenes. The people are very animated and you do have the feeling of sitting next to these characters listening to them.
Things to consider:
Face of the guy in the black waistcoat: Put a piece of paper over the eyes and look at the mouth, and then over the mouth and look at the eyes. The eyes are at an angle, but the mouth is straight.
Top right-hand corner: There isn't enough definition in this corner to hold the eye's attention, or possibly even draw it there at all. Compare it to the dark figure in the bottom left-hand corner, where the eye lingers making out a face and structure, and the suggested figures in others parts of the background crowd.
Depth of field: When you're looking at a scene, your eyes change focus continually so you don't actually experience depth of field. It's only when you look at a photo where the depth of field has been fixed on, for example, the foreground so that the background is out of focus, that you see it. This is one instance where, if this is the effect you want, painting from reference photos rather than real life can make things much easier.