y don't start with a base

I’m not any better but just from some tips I’ve seen from others, if you’re doing a waving animation like you’re doing there with the tail, try to make it have a few more frames. Like copying the ones before it so then it looks like it’s going back up and it’s smooth, rather than just cutting to the top again as it’s looping.

Try making the shape on one frame and trace and connect on the other frame

You can sketch first (if you want) and the arms are a little bit too long :>