There's a nice intro to computer animation at the SIGGRAPH web site http://www.siggraph.org/education/materials/HyperGraph/animation/anim0.htm that covers a lot of good general, elementary animation concepts. I troll used bookstores for animation books, too, and sometimes you find a real gem for not much money. Look for tutorials on 2D animation, too; there's some great techniques that have been around for decades in the cel animation field that are totally applicable to 3D animation.

For the kind of examples cited, I think the most important element is timing... you want to make sure that things move at a speed that looks natural, and that objects in contact react at a speed that makes them look as though they have the proper weight.

For example, when animating a punch, the arm throwing the punch is going to react to the transfer of momentum, not just the body it's contacting, and the energy of the punch will be transferred back into the body of the person throwing the punch.

I find it really helpful to go to YouTube and watch videos of people doing what I want to animate ('cause whatever you can think of, somebody's tried it and somebody else was on hand with a video camera). That gives a great feel for how many seconds it takes to do something.

If you're using Poser 7 or up, make sure to take advantage of the non-linear animation (animation layers), too; it'll save you some real hassle when combining moves. You can animate a character blinking on one layer and breathing on another, then add in your other moves on top of that.