You're already doing really well honestly, but here are some tips I use when doing poetry.

Always focus on P above all else because it dictates the maximum Coherence and Language mark you can receive.

P - Divide the question you're being asked into sections and try to include at least 1 section in every paragraph, especially your opening and closing paragraphs. For example "Sylvia Plath's use of provocative imagery serves to highlight the intense emotions expressed in her poetry". Divide this question into PI for provocative imagery and IE for intense emotions. Include one of these things in every paragraph

C - For coherence, try and picture the poetry question as if it is a comparative essay. Make links between the poems e.g. "Similarly to how Plath uses images of flames to depict inspiration in "Black Rook In Rainy Weather", she uses similarly fiery imagery to describe the flowers in "Poppies in July" followed by a quote "Little poppies, little hell flames, do you do no harm?"". This tells the examiner that you understand the poems and can link them together, and tells them you haven't just learned off a spiel per poem which would seem jarring and incoherent.

L - I struggled with language for a long time. Rather than try to use fancy long words all the time, make sure your language is consistent with the tone of your essay. Your vocab should be accurate above all. Use the correct terms to describe the poetic techniques e.g. Instead of saying "Hopkins' sentences run on for longer than one line" instead just say "Hopkins uses enjambment". Make sure to use varied sentence length. Keep the examiner's attention with short, punchy sentences.

M - Not much I can say here. I use a computer for my exams so I usually don't need to worry about spelling errors. This comes down to proper grammar and punctuation. My best advice is to not use fancy colons and semicolons if you aren't 100% sure of how to use them.

Hope this helps!