Have you checked all words you’re unsure of in a dictionary (especially commonly confused words such as: all right, all together, definitely, persuade).
Are sentences grammatical? Does every sentence have at least a subject and a verb? Are there any comma splices or sentence fragments? Do nouns and verbs agree (e.g., singular with singular, plural with plural)?
Are tenses consistent (e.g., present or past, not inappropriately mixed)?
Are commas correctly placed? Have you used too many? Have you used apostrophes correctly? Have you used a semi-colon instead of a colon, or vice versa? Have you divided a sentence with a semi-colon instead of a comma?
Have you used unfamiliar terms in their correct context? Are there any slang terms or contractions? Have you used the specialist terms for your subject?
Can you identify any clumsy wording? Are any sentences too long? Too complex?
Will the reader be able to easily follow your line of reasoning? Are your ideas expressed clearly? Is there a clear and logical progression from one point to the next? Are there enough signposts within and between paragraphs?
Does each paragraph focus on one central idea easily identified by the reader? Is the idea sufficiently expanded?
Do paragraphs link? Does the text flow smoothly and logically from one paragraph to the next?
Have you avoided making unsubstantiated claims or generalisations?
Is any idea or information mentioned more than once?
Is all source material fully and correctly cited? Have you avoided too many direct quotations?
Source: Planning and Writing University Assignments - University of Otago