When trying an artistic shot like this, I will often choose a subject or group that is still or moving less than the general crowd and use that subject or group as my "anchor since the subject or group should be sharper with the others milling around it.
Otherwise, we just shoot and hope - which is not all that invalid - since we cannot control the milling crowd.
In that case, the plan of action might be to shoot a very large number of images at different shutter speeds; hoping that one or two will turn out the way we desire. That is the advantage of digital vs. film. We can afford to shoot large numbers of images because the shooting is virtually free...
There is another technique which sometimes works. Use a relatively slow shutter speed, pick out a subject or group of subjects and zoom out while exposing. This is often better when the camera is stabilized with a tripod, a solid hold on an immovable object like a wall or possibly a monopod...
https://www.google.com/search?q=zoom...iw=960&bih=473