For this post, I will be review/describe some PHP resources
http://www.binarytides.com/35-techniques-to-enhance-your-php-code/: this site is a good guide for those new to PHP. It not only explains what to do, but provides pictures and good examples.
https://www.thegeekstuff.com/2014/04/optimize-php-code/: This resources is a good place to go once you know a bit about what your doing. It provides some good tips to make you PHP codes run smoother.
http://content.wisestep.com/how-to-become-a-good-php-developer-fantastic-tips/: A good series of tips. Excellent for beginners and professionals, it provides good general tips, not just specific to coding.
https://www.cyberciti.biz/tips/php-security-best-practices-tutorial.html: a good series of security tips. Not only does it provide specifics for php, but some of these tips are good for coding security in general.
http://toppersworld.com/top-10-php-debugging-tools-for-web-developers/: a series of debugging tools, complete with links to the tools. It also provides a image of what the tools look like and a short description about it. Note: it seems the last item is no longer available for use as the link to it is crossed out.