Steps to develop pluguins
I want to know what are all the step to develop a plugin(initial)
You define an interface, and implement it in a library, which you load dynamically.
If you specify what you want more clearly, then perhaps somebody can give you a more detailed answer.
You can also check the "tutorial":http://www.voidrealms.com/viewtutorial.aspx?id=246 here and there are other tutorials for Qt that will be helpful. "Qt Tutorials":http://www.voidrealms.com/tutorials.aspx?filter=qt