An offshore development project needs the same clear ownership as a local one. Decide who sets priorities, who accepts completed work and how questions will be resolved when working hours only partly overlap.
Break the work into reviewable steps and ask for working demonstrations. Agree on testing, documentation and handover arrangements before the project reaches its final week.
Security requirements should also be part of the brief. NIST's Secure Software Development Framework provides a vocabulary for discussing secure development with suppliers, including protecting code and responding to vulnerabilities.
Keep access proportionate to the job and make sure the business can maintain the system after the contract ends. A lower hourly rate is only one part of the overall cost.