You can try to animate the "key-frames" first, then animate the "in-between" frames next. Key-frames are your key parts of the action and the in-between frames are every other frame between the key-frames leading up to the moment of action. You should draw the first frame and the last frame of the action as your keyframes (minimal amount of key-frames should be 2 but can end up with more).

Let’s say for example an action is 5 frames long. Your keyframes are frames 1 and 5. Draw them first. Your in-between frames will be frames 2 through 4. Draw in frame 3 first as your mid point. This will help not only to keep your animation smooth but also maintain your proportion. After you animate frame 3, then you can draw in frames 2 or 4 (it doesn’t matter which one first).

Eventually your animations could become more complicated and may require more key-frames. Hope this helps.
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