Best way to move domain.com/blog-title/ over to domain.com/blog/blog-title?

Hi I'm realising I should included "blog" into the slug as it makes a few more downstream analysis processes a bit easier. What would be the steps to do this without penalising my site?
You should set up the parent slug (blog) first before you do any redirecting. The redirects should handle themselves but may not. A 301 redirect using a .htaccess file is the best way to move your blog.