Plugins

firstly, you need to learn PHP
no exceptions you must know the basic of PHP
secondly, you need to learn OOP for PHP
no exceptions same as the first
Both steps are very important and crucial so do not skip them
thirdly, Boom you now magically know how to make pm plugin, weather from looking into the source code OR looking into other users plugins you should have absuletly no problem at all reading or understanding PM once you finished step one and two

And the best thing is there a website for everything you need to know in order to learn PHP, it's PHP.net
And here is a handy link http://php.net/manual/en/langref.php
just learn every chapter/resume off from where you last left off and you should be all set

not every thing is needed to understand PM, but it is essential to optimize PHP to it's fullest potential

 

but if you have learn PHP you wont be just blindly copying code, you actually KNOW what it does
which make a difference from copying and coding

 

By "learning" we don't mean going to a particular website or college or buying a book to learn it. As long as it is in-depth understanding, it is OK. Many people claim to have "learnt" PHP, but they don't really understand why we need to use classes at all.
As a matter of fact, many of us here have never learnt PHP properly, but managed to create legend by pure talent.
To be exact, "first you need to learn PHP" is the simple answer we give to people who ask the broad question "how to write plugins". All roads lead to Rome -- how would we know which method is the best for you, an individual?