For me, the hardest part of writing is finding the words to match what I am thinking. Often times I find myself staring at a blank page trying to display my goal in what I am writing while still making it my own. Usually, I write the best when I am passionate about the topic of my work. This helps me feel good about what I am writing, find the words a bit easier, and write more because I am knowledgeable about said topic.
A few of the steps I take to writing something good are reviewing what I know about what I am writing about, making a rough draft and going over it, and taking my time to figure out what I can improve on as I go along. As far as helping a struggling writer, I could find out what is blocking them when they are writing. If they are finding it difficult to set up their paragraphs then I would guide them through that. If they are struggling with something like not being able to relate to what they are writing or not connecting to it then I would suggest they do more research and/or think about little things in their life that could connect to said topic.