Am I the only one who now hates the two sided poster thing back in like 2012? Like, back then, yeah I thought “That’s so cool!”… Now it’s like… Really edgy?… Like I don’t get the appeal by it other than showing a Character’s “insane” side
Constant practice, using lots of references and focusing on learning anatomy helps. Referencing is particularly important because it’ll help you to be able to see what to improve. I recommend a lot to look at DimFann.
You can also check my Anatomy Equilibrium gallery if you want generally well made anatomy to learn from.