Originally posted by BruceBanner fairly wide portrait shot of someone
That's the first flaw I saw in your strategy, as much as I'm a fanatic for adding context to the photos I take, I always end up with lousy results unless I can get lots of isolation for the primary subject. You could clear the crowd by yelling "He's got a gun!" or put your subject far enough away from the steps or other reference point to make the background actors much smaller than your primary subject. Usually the crowd thins out as you get further away from steps, doorways, statues and sidewalks. If you want the ghosting effect of long or multiple exposures, your subject has to stay extremely still to remain sharp in the final image, hence it usually works best with inanimate subjects. Even the very best masking tools in PP will somewhat reduce the sharpness of your final image, so photoshopping works best with smaller images or images where the offending artifacts are somewhat isolated from the good artifacts that you want to keep in the image. Its always better to keep a little distance in photos between your favorite niece and the useless twit she married so you can take him out of the picture when their relationship inevitably goes south.