Half the learning aspect of improving one's poetry is reading others' poetry -- I recommend the anthologies published by Bloodaxe Books, especially the 'trilogy' ... Staying Alive, Being Alive & Being Human - (each with about 500 poems in them)
Yeppers to this.
I'd say another big chunk is seriously listening to opinions of your writing. IF you've put your ego aside, the "valid" opinions will resonate.
Understanding the language you work with is the rest of the battle. That means Grammar, Spelling, & Punctuation. Here is a thread regarding Punctuation: https://deepundergroundpoetry.com/forum/workshop/read/11232/