@Croft: your words are reasonable, but what to do when there is no plan? How to play if I don't know what actually to play? How to produce an idea which could be character's background, guidance to follow, main story line?
If considering only in-game actions and interactions, I hardly be able to create my own part of consistent roleplay, all I could is follow someone's roleplay and lore.
It is better to have a bad plan rather than not to have any.
Also I had a thought that to create something, I have to learn on others works, I have to find an inspiration, a spark, that will lead my mind in the new direction further than ones got before me.
Roleplay is writing, and each author became a writer under inspiration of previous writers and their experience.
If this game was abouth mathematics, we would have to study it to reach the highest level and only then create own theories and researches.
Just like whole world works - you have to learn the experience of many of your ancestors to have a foundation for building own thoughts...
They've spent lives of effort to put their experience into the books (mostly), and we are now given an opportunnity to read and learn them...
It took me a bit off the topic, but it helped me to re-assign my thoughts, and understand the importance of experience when it comes to art, in this particular case.