Important - the length of the content is determined by how much you can usefully say. Do not attempt to write 1,000 words or more just because SEO theory says that is necessary. Write what is necessary to convince the user. Mark Twain said something like "if I'd had more time, I would have written less."
Important - when countiing the number of occurences of a word, variants of words count. So "We deliver flowers. Use our super-duper delivery service" uses the word deliver TWICE.