Avoid spending too much time on any one specific area, keep moving around. When I was in school, we were often taught that the first line you draw should be the midline of the body, from head to toe (assuming you're drawing a person, of course). Then move to marking the major joints of the body, like the shoulders, neck, elbows, hips, knees, etc. Be sure to also draw horizontal lines across the body to indicate the angle of the shoulders, hips and torso, and often the knees as well - this will help give you a quick indication if your placement of the major joints is off.
Do all of this without ever once lifting your pencil. My foundation drawing teacher would see who in the class could make the most convincing gestures with the fewest lines (difficult when your pencil can never leave the paper).
Also, practice gestures with different time limits. We would work on separate gestures for 3 minutes, then one minute, then 30 seconds, then 10 seconds, then finally five seconds. Gestures are a great exercise for speed versus accuracy, with enough practice you'd be surprised what you can draw in five seconds.