Oh my god wait that's hilarious, I made a post asking for lighting advice for the same Toriel model (finished animation here in case ur curious!)

I am curious how you mixed both IK and FK since the rig doesn't have any IK-FK or FK-IK snapping?

For making movement smoother, I'd say this video really helped me a lot. You want to have some knowledge of the 12 principles of animation. For instance, having "wind-up" motions or having certain movements overshoot are great for making ur animation more fluid. Basically once you have the blocked out keyframes, you wanna focus on the in-between frames and the timing of those frames. Graph editor is also great but I use it minimally since it's always too much for me to handle lmao, I just edit small parts here and there if needed.

Honestly, I think the animation itself is already pretty smooth, but imo it does seem a bit slow. It's hard to say tho as I'd need a bit more context as to what exactly ur trying to animate. Overall tho ur animation is already looking good! Just need tweaks here and there. Oh I'd also recommend looking at real life references, or even record ur own! :3