Some common factors to include in a freelance contract are:
Recitals: Include the who, what, when, where, and how in your contract.
Duration: Getting an estimated duration of the project would help you as a freelancer in the case where you would require additional time to make any changes.
Timeline: Include a timeline for your clients as well so that they can reply with any requests or queries for you. This can help you structure your future tasks as well.
Deliverables: Ensure to mention the way you would be delivering the files to your client. This can be done to avoid any miscommunication and last-moment changes to the file types.
Remuneration: Freelancers usually charge by the hour. The payment terms should be mentioned and followed clearly to avoid any confusion in the future.
Cancellation policy: In some cases, a project may get canceled after you start working on it. Without a contract, you may not get paid at all. Therefore, ensure to include a cancellation clause in your contract.
General conditions: These may include the laws of the land, non-disclosure agreements, confidentiality, and so on.