It is a good practice to have your website work with both www and non-www domain (ie. vs. ) domain. Only one of those domains however should be defined as canonical domain for your website.
When referring to URLs in your website decide if you want to use URLs with or without trailing slash (ie. vs. and use them consistently throughout the whole site.
When using multiple URLs for site associate the public URL of your website with the Internet Zone.
When building custom Display Templates for Content Search Web Part always build a corresponding XSL Style Sheet and link it to your Display Template.
When working with cross-site publishing it might just happen that the XML Sitemap for your site is not being generated anymore. Find out what the reason for this is and, what’s more important, how to fix it.