I'm starting a new animation before I finish the other one, but I thought it'd be helpful to showcase how my animations function.
Firstly, I keyframe every bone on the body to help keep the graph editor clean, you don't want to have to work out which bone is keyed on which frame, and besides when the program automatically smoothens the animation by splining it, it'll smooth from one keyframe to the next. That can cause bones to start moving before you'd like them to if there's keys where a bone isn't framed. It's best to just avoid that and key everything in stepped mode (Keys jump from one to the next, like stop motion.).
Secondly, I don't have any set rhythm in which I place keys. On the graph you can see they're all quite evenly spaced out, but that won't always be the case. I key my frames based on the driving action of a character. For this shot, the driving action is the foot, and I animate everything around that. This usually involves animating the pelvis and foot first, then going back and animating the arms, head, shoulders, etc.
Thirdly, accounting for physics and inertia. Since the foot is the driving action, everything lags behind as they follow it. The torso is connected to the foot, but doesn't lag behind as much as the connection between the two is quite rigid, and the arms follow the torso on a delay. It's a hierarchy of chain reactions, keeping that in mind will make your animations much smoother and more realistic.















