Blocking plus in 3d animation is the stage that follows the first blocking stage. After finishing the key poses in the initial blocking stage, by doing blocking plus will help with the accuracy of the animation. Generally speaking, blocking plus is a process which includes more detail and subtle movements.
I review my blocking first then refine the key poses. I went to each key poses and refine each of them. It is necessary to pay attention to the shape and proportions of the poses. After the blocking plus, the animation looks more polished.
I try to pay attention to the timing between poses, just so I can be sure that the animation feels more natural.