Here are some useful web resources that assisted during the development process of my website/blog (a never ending process).
Web Design in 4 minutes - Jeremy Thomas
Aimed at the up and coming web developer, this interactive article describes the CSS necessary to style a webpage. Not every CSS style suggested by the article will appeal to everybody, but they are all great starting points.
Pingdom Website Speed Test
If you care about web performance and loading times, then you definitely want to check out the Pingdom's website performance tool. This tool lets you view millisecond latencies for DNS requests, subsequent GET requests, total page load time, etc., from various servers around the world.
DirtyMarkup: HTML Beautifier
This is my preferred tool for cleaning dirty HTML and CSS! Check the source code of my homepage for an example of the tool's output.
google-webfonts-helper by Mario Ranftl
If you want to use web fonts from Google, but dislike Google's tracking, then the next tool is for you! The following lets you select and preview web fonts from Google, and download them for self-hosting.
In case your website ever needed more math on it, KaTex is a lightweight LaTex typesetting solution for you.
Commento commenting platform
Commento provides a lightweight alternative to Disqus, the currently de facto standard for comments. Its benefits are fast loading times, and (apparently) privacy focused design.
Benchmark your site using programs such as apachebench and httperf! You can find out how many users your site can handle, and try to increase your site's performance before a hug-of-death.