Before starting a project with a vendor, it's important to set clear expectations. To do this, you should define the project scope and deliverables in detail and document them in a contract or statement of work (SOW). Establish the roles and responsibilities of each party and communicate them clearly. Agree on the project timeline, milestones, and deadlines and update them as needed. Set the project budget and payment terms, track the actual costs, and monitor invoices. Define the quality standards for the project deliverables and test them before acceptance. Additionally, determine the communication methods, frequency, channels, and use them consistently. Identify potential risks or issues that may affect the project and plan how to mitigate or resolve them. Lastly, define key performance indicators (KPIs) and metrics to measure success and report them regularly.