I always find it kind of strange if some one is using digital media for lifedrawing but that s just a personal thing.
but I can suggest some things: looks like you used the same brush size all the time. try to use a big/huge brush at the beginning to block in the whole figure. when you do that, think about the surfaces which create the figure, think about the construction. don't worry about details. squint your eyes to see the main surfaces/areas better.
below some of my recent life drawings all done with pencil