Here are some questions you may wish to ask yourself about tone, language and style before starting an assignment:

Language	Should your writing be informative, descriptive, critical, argumentative, reflective? A combination of several styles? First person or third person? Any technical or subject-specific language you will need to use? Any terms that need defining or unpicking? How can you make your language as clear and concise as possible?
Features	Does your work need an introduction? A conclusion? How long should they be? Are there other sections needed, such as an abstract, a methodology section, a results section? Should your assignment be putting forward an argument, and does this need to be stated in the introduction? How much reading might you need to include in your assignment? Are any real-life examples required?
Layout	Should you use sub-headings? Are there any other features of layout to think about e.g. indenting paragraphs; use of page numbers; headers or footers; line spacing? Are there any layout conventions of this type of document?
Other comments/ considerations	What kind of tone might you need to strike for this assignment? What might be the purpose of the assignment and who is the intended or implied audience?