Pre-launch activities
The first thing that we need to do before we give the all-clear for site launch readiness is a final quality assurance (QA) check. Even though you (hopefully) unit tested, did an end-to-end (E2E) test, and ran User Acceptance Testing (UAT), remember that UAT might have required significant changes to your development and architecture. If you enabled enhancement requests or fixed bugs, you need to run an additional check. It is great that you have your UAT all buttoned up, but you need to run one final E2E QA task to ensure your new sites work without error.
You might be surprised how many times things are caught in that final E2E test, in addition to how often it will help you determine how to sequence deployment activities. If this is a brand-new site, you can also have it moved to dark production and do the final check live in production before granting external access. The trick before you start moving items is to ensure that you pass technical readiness...