The following things to note when you deploy a new Sitefinity site to production environment:

1. Check the site authentication mode. It must have only one authentication. Check “Anonymous” and un-check “Integrated windows”
2. Check Theme style link binding. Sometimes you need to add aspnet_isapi.dll wildcard in order to make the theme work again.
   IIS > Website > Properties > Home directory tab > Configuration > Wildcard application maps > Add (C:\WINDOWS\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll)
   Make sure to UNCHECK “Verify that file exists” or you will have 404 errors everywhere.
3. Check if your server have all required MIME types eg. Silverlight MIMEs
4. Give the website folder “ASPNET” and “NETWORK SERVICE” WRITE access
5. Reindex all your search indexes.
6. Update your license file to correct site domain license

… will add more as I find things later.