The SEO checks that should be built into planning, design, migration and launch rather than left until the end.
Start with the commercial question
Before choosing tactics, define the business outcome, the audience behaviour that can influence it and the evidence available today. This keeps design, content and technical decisions connected to a measurable purpose.
Build the fundamentals into delivery
Strong execution is usually the result of many disciplined decisions: clear hierarchy, useful content, accessible interaction, responsive behaviour, fast loading, reliable measurement and a publishing model that teams can maintain.
Measure what changes
Decide how success will be evaluated before launch. Use a small set of relevant measures and review them alongside qualitative feedback so optimisation is based on evidence rather than preference.
Make improvement continuous
Launch should create a better platform for learning, not a fixed endpoint. Maintain a prioritised backlog and improve the highest-value areas as new evidence appears.