Firstly, there is absolutely no shame in beginning with 2-minute gestures until you feel comfortable. On the contrary, take that time to get the muscle memory and eye practice, and then after a while cut it down to 90 seconds, 60 seconds, 30 seconds. There's no rule saying you should stick below x seconds, but you can try to choose a time that's juuust a bit too short for you, so you don't get stuck with the details. The point is to force yourself to work on the big things first!
I agree with Kayke in that you should start with the whole, then go into individual body parts. (Lots of great advice from her!) Here's something I whipped together to describe how I go about gesture drawing, I just picked the first pic that came up on the fantastic link kayke shared. (Disclaimer: I'm. not. a. pro.)
As I was starting out with gesture drawing I first only did lines of action for poses (which should always be a simple line - C, S, or I). This is really abstract, but try to think of it as if you simplify the whole pose, the intent behind it, into that one line, in this case "about to cut". Then I moved to the shape, trying to distill the poses into one solid shape. This helps immensely with building awareness for the silhouette of the pose, which determines both the legibility and "drama level".
The next step is to draw in the simplest shapes of the pose you can, fitting them as closely as possible to the shape you drew. Don't be afraid to exaggerate, as you can see I bent the back and front knee more. Of course you can push it much, much further if you so wish! I don't actually draw out the second step every time anymore, but I do draw the line of action and then keep the shape in mind when drawing the gesture. It's still there - just mentally.
Now if you have time left, you can begin blocking in shades if needed, and/or add more parts to the drawing. Don't dive into details, it's more of a natural continuation of the third step: Keep adding the next most important thing to make the drawing understandable until your time runs out.
Oh and another thing: I added a foot! If you feel that the photo is lacking something, or if you can just do this one little thing to make the whole pose more impactful, such as moving the arm a little or turning the head a little.. or a lot.. do it! I felt that leaving the foot out would look a little strange, as if I'd forgotten it, while drawing it in would emphasize that step forward. (That being said, I'm nooot quite sure what the model is attempting to do. I instead ascribed the meaning "about to cut" to him and went with that.)