I've always been frustrated to improve my gesture/ observational drawings but lately found the work of Matt Jones, who showed me how much fun it is to use your imagination when sketching! The following are attempts at infusing real people with my own brain juices. It's a lot of fun and a great way to refresh creatively! Try it!
NOTE: Sometimes people are doing such interesting things that you don't actually have to use your imagination. Case in point? Top right guy holding a coffee between his teeth while he texted. New Yorkers sure LOVE their mobiles (remember when we called them mobiles?)
Also, Matt Jones does a great job of pushing his gestures and storytelling!