>>16428579aye don't feel bad man, latex is ridiculously hard to draw cuz of how reflective it is
I don't really get it either
My understanding of it goes like:
the parts that stick out the most n catch more light get the highlights n then those spots on the opposite side from where the light is coming from u put the darkest shadows
then u can put a mid tone for places that don't stick out as much but still get some light if that makes sense lol
I also usually put highlights on the edges cuz those catch light too
u already seem to get the basics of it w how u placed the highlights so u might just need to practice it a bit more
don't know if that helps but uhhh
ye
the best way to learn how to draw anything is to kinda just draw the thing over and over (have it irl if possible) and also taking stuff from tutorials or art books