Hello! I've moved my blog (sallonoroff.co.uk) from a self-hosted WP to Jekyll on GitHub Pages. This site is largely based on Poole but has had numerous modifications, hacks and bodges applied. You might find some of the code here useful to copy, but I'm not sure it'd be a good idea to fork the whole site.
Here's a list of pages that have helped along the way.
Guides
http://jmcglone.com/guides/github-pages/
https://www.smashingmagazine.com/2014/08/build-blog-jekyll-github-pages/
http://joshualande.com/jekyll-github-pages-poole
http://pixelcog.com/blog/2013/jekyll-from-scratch-core-architecture/
https://michaelsoolee.com/jekyll-post-page/
Plus inspiration taken from...
https://github.com/poole/poole
https://github.com/dyutibarma/monochrome
https://github.com/chrishouse/chris-dot-house
Cheat sheets
https://learn.cloudcannon.com/jekyll-cheat-sheet/
https://gist.github.com/smutnyleszek/9803727/
WordPress to Jekyll conversion
https://ben.balter.com/wordpress-to-jekyll-exporter/
https://vitobotta.com/2011/03/28/migrate-from-wordpress-to-jekyll/
(Not to mention lots of help from BBEdit to tidy things up)
Making an archive
http://reyhan.org/2013/03/jekyll-archive-without-plugins.html
http://chris.house/blog/building-a-simple-archive-page-with-jekyll/
Tags
https://codinfox.github.io/dev/2015/03/06/use-tags-and-categories-in-your-jekyll-based-github-pages/
https://www.yizehu.com/2017/06/19/sort-tags-in-jekyll
https://blog.lanyonm.org/articles/2013/11/21/alphabetize-jekyll-page-tags-pure-liquid.html
http://pavdmyt.com/how-to-implement-tags-at-jekyll-website/
(Not forgetting CSS to make tag icons here or here)
Fixing pagination in Poole when your posts are at /blog
https://stackoverflow.com/questions/24717458/creating-a-website-with-jekyll-that-has-a-subdirectory-for-the-blog-with-paginat
https://github.com/bpatra/jekyllsiteblogpaginated
Other useful stuff
https://blog.webjeda.com/jekyll-related-posts/
https://zzz.buzz/2016/02/13/add-an-updated-field-to-your-jekyll-site/
http://www.benjaminday.co.uk/blog/misc/2015/01/08/github-pages-and-123-reg-dns/
http://adam.garrett-harris.com/how-to-easily-embed-youtube-videos-in-jekyll-sites-without-a-plugin/
https://avexdesigns.com/responsive-youtube-embed
Many thanks to the authors of these articles.