The first and foremost characteristic of great poetry is vigor of imaginative power, which enables the poets to create things quite new, a magnificent world of beauty and ideas for the enlightenment and delight of the readers.
Poetry is at the pinnacle of the writing endeavour. It is where your skill with the English language counts the most. If you suck at grammar, don’t try poetry; first, learn your language. Maybe this will point you in the right direction.