Maybe this question sounds wide but deep down it is not, I'm still not formed in anything so I only have bad practices in the back and wanted to learn to program in a way not only "standard" but clear and clean .
Programming standards with security and simplicity
See, when I say programming patterns I mean how to write code in a healthy and simple way ... Reading and searching I found some tips that can help, such are:
$userBrowser = $_SERVER...
I have known these three, they must have others .. If you know other cite maximum 3 that are not listed above ...
and security, where do you go?
Well, I have small ticks with security, fear maybe and as I'm always programming server side PHP and client (ex: JS)