A brief description of your project. What does it do? What technologies does it use? What problem does it solve?
Instructions for how to install your project. This could include software dependencies, environment variables, and so on.
Instructions for how to use your project. This could include code examples, screenshots, etc.
Details about how others can contribute to your project. This could include steps for filing bugs, code standards, and so on.
Information about the license your project uses.