They're very bean-shaped, so that's now I usually divide them lol
That bean shape can usually be broken down into a top and bottom half, or loose circles (torso and waist). Usually it's a sorta tear drop shape that flows into their legs, like with Sonic/Shadow/Knuckles, etc. Tails has the opposite, and has a little more weight to his body, almost like a malleable bean bag. Characters like Vector are sorta the outlier, because their spine flows straight into the back of their head. Once you get that S curve down though, he's not too difficult.
Not sure how much this helps, but just a little breakdown that I personally use