Are there any others I realistically am going to need to know, or will those be able to keep me covered!
If I were you, I’d only focus on the four you listed, they’d get you pretty far! Hope I helped!
Source(s): My own knowledge
Server side in addition to PHP for server side behaviour you probably should take a look at SQL to understand how data is stored and retrieved.
In addition its always useful to see a different approach to constructing systems. PHP is embedded inside HTML and pushes out data. It would be worth looking at C# and how its used with ASP.NET, instead of having code inside HTML that is pushed out, HTML in ASP.NET pulls data things exposed by the C#.
Additionally, or perhaps instead of C#, you could look at Java, which tends to be used in the PHP model of pushing data into HTML.
Server development has some language to choose, such as php, asp.net, java.
php is simple script language, it has a lot of open sources to study.
wordpress system is large blog system, it includes much design method,
you can refer to it.