Hi, mates! When you shot a video with a hand-held camera, it usually ends trembling a little. Some cameras have integrated stabilization while you're filming, but generally, that may not be enough. In Blender, you can use the Movie Clip Editor to track points in a video, and use that information to compensate their movement in order to stabilize the video. In this tutorial, you'll learn how to track features in a video, and use those markers to stabilize the video. Finally, you'll apply that stabilization to the final output in the compositor.
Also, make sure to check out my book, "Learning Blender - A Hands On Guide to Creating 3D Animated Characters", which is already available in paperback and ebook versions.