My thumbnails are pretty illegible!

These are literally an inch wide, and that's the big version! Before I make these nice ""neat"" ones, I've usually worked out a lot of timing in the margins of my script--
--where there's a lot of trial and error and reworking.
My main goal with the thumnbails is to figure out how all the panels are going to be laid out and how much space I want them to take up, that sort of thing. Those little scribbled figures are just my first instinct when it comes to how the characters are gonna be in the frame -- a lot of times that changes later, and I don't worry too much about it at this point.
The step after that, which I call "roughs" is where I start paying attention to my camera angles and shot calls, and making sure everything still flows well:
I draw the rough sketch at about half the size of the finished page, since working small keeps me from making everything too tiny. In terms of keeping things varied, one trick someone told me was to look at all the entire page and see if all the figures on the page are roughly the same size -- because that means it's the same type of camera shot over and over. If I see I've got that going on, I'll look for places to kinda mix it up a little bit, but otherwise I try not to swing the camera around too much just to do it.
I..... don't know if this actually answers your question!! But this is sorta how I approach the process; if there's something I can go into a little more, by all means feel free to ask x3