It's just a process you have to learn. I think it's important to know the different sections of the spine and how they curve. Once you get the spine (or midline of the front of the torso) down, you can draw a line for the angle of the shoulders and another for the angle of the hips. From there, try to capture what the weight bearing leg is up to, followed by the other leg, and then the arms. You can see some of my gesture drawings below; I worked from the outside and spiraled in, so you can see how they become more fluid as they get toward the center. It's really a lot of fun to do once you get into the zone.
Nah, it was more like 3 sittings for 5-6 hours total. I'd recommend drawing a grid so you sort of have a boundary of how big and crazy your little people are going to get. If 30s is too quick, there's really no harm in doing 45 / 60 / 90s studies. Just do it at a speed that's comfortable where you can get the idea out. It'll get faster and easier the more you do. Ctrl+Paint has a couple seriously good videos on the hows and why's of gesture drawing, I'd recommend them to anyone interested in anything: [link] [link]
Im in the same boat. I've been trying to work on my gesture drawing as well, using pixellovelys model slideshows. Heres what I came up with earlier [link] . I'm trying to use skeletons to get the line of action as well as keep track of proportion until I get better at doing this. I've mostly been doing the 30 second ones, and I did do a 1 min session.
Ive tried watching videos of others sketch and its not that helpful, not yet at least. I believe you have to train your eye to see the line of action immediately and sketch it without really thinking about how to get it on paper. I'm still a novice at it though.
Just do a lot of them. A lot. They will be very stiff in the beginning, but eventually you will learn what is necessary to convey the pose and what isn't, and they will become more fluid. Like shininginthedarkness said, timing yourself is an excellent idea. I don't reccomend posemaniacs.com, though - right now you want to focus on movement and how the human boody look, and not on the unnecessary details of muscle mass.
If you don't want to draw from life for some reason, I would suggest the gesture drawing tools housed at pixelovely (google it, it's difficult to find through the main site) or lovecastle.com. Both have engines that show you a random photo of a clothed or nude person during a specified amount of time, such as 30 seconds, a minute, or up till an hour. Pixelovely have pictures of animals and timed classes, lovecastle have pictures of faces, and I'd suggest checking out both because they both have their strengths and nifty features worth checking out.
They don't beat drawing a real-life model, but in the absence of one of those, I think those sites are great alternatives!
They're a good start! There are downsides to working with a 'style' when you are practicing anatomy and proportions, however. (damn, I already know this is going to be a rand x( ) When you are drawing an anime face, what you are really drawing is a human face that have been simplified. You are still drawing a human face, though, and knowing the basic anatomy of the thing you are drawing, is going to help you immensely. Having an understanding of the human face in a realism-sense, is going to help you spot mistakes in your anime drawings that you previously would've overlooked, but that more experienced artists could point out easily.
Many anime and manga artists fall on that regard. If you study the cover of manga books, you'll notice that some have very fluid-looking characters even if they stand still ([link]) while others have 'dynamic' poses but look stiff anyways([link]).
Now, some people might not be bothered by the second example. Other people might be thrown off by the fact that the shoulders are completely fixed in place there they should be more fluent and loose, and that the spines are bent in an unrealistic way. The difference is that the first artist know how realistic anatomy is supposed to look, then applies a manga style on top of that knowledge. The second one probably learned to draw by copying another manga artist, and thus doesn't know how to fix or perhaps even spot their errors.
Sorry for the rant, but I hope the point came across. Your biggest error right now is that you remember your style, while you should forget it for the moment and try to learn something from scratch Studying muscle groups and bone structure along with gesture drawings is a great thing to do as well. You can probably find a good anatomy book in a public library if you have access to such a place.