First you should brainstorm and once you've got your ideas for whatever you're writing, you split it into topics, if it's an essay it's usually five paragraphs (an intro, three body paragraphs, and a conclusion but you can have any amount of body para.) then you write in general what you want to cover. Make sure you have enough sentences, and then start working on your rough draft
look at the singular words that describe things for example "a" and look athe words "their" and things to know the difference of a plural and singular.