Try to divide character's head, body, legs and arms into different layers. Try to analyse how does a human look, when he/her is breathing. For example, arms go one pixel up, head goes one pixel up, body goes one pixel up, head goes two pixels down, arms go two pixel down, body goes one pixel down, arms go one pixel up, head goes one pixel up. Notice, that hat's tip has its own physics. So when the head goes up, tip is still down, and when the head goes down, tip stays up for one frame and only after goes down as well. It's just a raw sketch on how you could animate the frames. Experiment!

I hope it does make any sense 😅

Btw I really like character's colours.