Delivery Checklist

Build 404 Page
Make sure that a Favicon is present. 

BrowserStack IE/Mobile Test

Key Page Speed Test (Under 2 Seconds) -
Insert Analytics / Retargeting Pixel / HotJar
Sitemap, Robots.txt, Check Meta Data
Complete Final Amends (If applicable) 
White Glove Amends (1h Max) 
Do your happy dance, Drink a beer (Maybe Both)

Setup Email Sending Domains for DKIM  How to set up your email sending domains

Setup 301 Redirect from the non-www version of the domain to the www version via the DNS provider. More Info...
Meta Tags: address meta tags for key pages first, then as time allows, do all pages in footer of website.
Google Webmaster Tools: add the site, which includes verifying with a header code, and then loading the sitemaps.