Here's the process I went about animating Sonic in case you were curious! :D
-Keys. Only the *most* necessary key poses to get the point across. Reads more like a comic or slide presentation at this stage.
-Extremes. Like keys, but more of them. They help define the actual rhythm of the animation. They're also the strongest drawings alongside keys.
-Breakdowns. This is the fun part. The breakdowns are drawings between the extremes that describe the actual movement of the animation and *how* the poses change. This is where a lot of the *life* and volume comes in and it's perfectly acceptable to just leave animation at this stage, especially on a budget.
-Animation Passes. Using my breakdown passes as goalposts, I straight-ahead individual parts of the body based on what is leading the action. This part can be scary and tedious, and it's good at revealing flaws in your animation, but can add a fun "wow" factor. Again, not a necessary step, but I felt great after I finished it.