In my first rough pass, I'll block out the main storytelling drawings, playblast it, and then retime those main beats accordingly. It's mostly trial and error. You want to get an interesting sense of timing moving in and out of your main ideas.
After that, I take reference of myself. This always gives me even more interesting ideas in terms of timing my acting ideas. Once I have that rough blocking pass established, I'll put the reference away and see if I can continue to plus the timing by trial and error. Tweaking the timing of your scene is something that you can refine throughout the entire animation process. Hope that helps!