Whatever 3D animating program that you're using, there should be an area in your options that allows you to control your rendering output. Just turn off everything except what's necessary--the basic shapes, possibly the bone/control structures--to significantly cut down on your render time, as now the rendering engine will have far fewer calculations to process for each frame. Also, in your scene, hide any objects that aren't an essential part of your animation, including environmental factors that aren't a part of the motion that you're focusing on.
Just making those few adjustments should minimize your rendering time significantly, allowing you to test your motion sequences quickly. When you're ready for your detailed renders, you can always open your options again and turn those settings back on.

