Drawing people is ALWAYS a challenge and drawing crowds of people is a mega-challenge. There is really no way to do it other than to keep it really, really simple. A bunch of circles for heads, a few vertical lines for bodies and legs and a few dots of colour in the multitude of skin tones.
I'd like to upload my sketches, but I just discovered that Weebly, the blog software I use is being a dick by insisting I upgrade. If I can't work it out, I may have to switch to Wordpress or Blogger. Stay tuned.
In the meantime, if you are on Facebook, I've uploaded them there.