A checklist for migrating your old content to your new domain

Pre-Move

Make a backup and copy of your current website.
Move a copy of the website to the new web hosting account.
Crawl your website, saving URLs and other data in a spreadsheet. Make a URL list for 301 Permanent Redirects.
Review current site for references to the old domain, update copy, and make-ready for the new domain name.
Perform due diligence on the domain name you’re moving to.
Check links to your current website, making note of most powerful links from other websites.
Verify site in Google Search Console, Bing Webmaster Tools, other search engines. Include both the current and new domain you’re moving to.
Submit URLs of the new website to Baidu, other search engines that accept submitted URLs.
Write a press release about your brand moving to the new domain name.
Set up HTTPs for the new domain name.
Consider using Canonical Tags to point from old to new domain. Make content live on the new domain for 3 months, then redirect later.

Plan a date and time to move to the new domain.
Detail the process for moving. Who is responsible for what (in your organization)?

Add 301 Permanent Redirects to the new domain name
Test redirects using server header check. Ask a friend in another location (using another ISP) to check the redirects to make sure they are working properly.
Crawl new website, checking for internal errors, any references to the old domain name. Fix all errors found.
Notify Google of change of URL address.
Update Google Analytics with the new domain.
Check Google Analytics for referring URLs (sites sending traffic), notify those sites about the change of domain.
Update social media profiles with the new domain name.
Update email signatures, email addresses with the new domain name.
Update business cards with the new email address, new domain name.
Update company internal themes/documents with the new domain name.
Update company newsletter with the new domain name (send out a newsletter?).
Distribute a press release about moving to the new domain name.
Update PPC campaigns with the new domain, run new PPC campaigns to compensate for any traffic loss.
Notify your customers, clients, and business partners about moving to the new domain name.
Contact link owners of most powerful links to the old site. Tell them about the new domain name.

Watch Google Analytics for changes in traffic.
Watch the current site for any search engine ranking changes.
Work on getting new links to the new domain name.
Start a new marketing campaign(s) to help awareness of new domain name in the marketplace.

Note: Thanks to the DNA and Globerunner for providing this checklist.