When drawing a manga character, the right proportions are important. You are about 7.5 heads tall. Manga action heroes tend to have more elongated proportions, at least 8 heads tall, often taller. The comparatively small head heightens the dramatic effect of a low viewpoint in the towering ‘hero’ stance. This is a very different look to the big-headed style of cartoon.
Otherwise body proportions are pretty much standard: your shoulder to your elbow is roughly the same length as your elbow to your wrist. The same goes for the hip to the knee and knee to the ankle. I generally like to begin the wireframe figure by placing (not finishing) the head, then going into the rest of the wireframe, because the head usually guides the body. The detail is developed along with the rest of the figure, not finished first.