You can only make plugins using a programing language that allows you to compile dll's. Even then there is only a few languages that can compile dll's that are compatable with plus.
The only languages that have sucesfully been used to make plugins are: VB, C/C++, Delphi, .net languages, and ASM i think.
All of these languages require some programing knowlage, and you can use an editor like flash mx to make the plugins simply.
So in short, the only way to make a plugin is by learning one of the languages, and reading the
plugin api documentation. I would recomend VB if you are new to programing.