Determinism In Musical Composition

How much is it possible to determine what is your next composing piece is going to be like before you put down your first note?Form,tonality,mode is not considered as very much deterministic of a musical composition.

In other words how much do you plan about your composition?If you are asked that tell something about one of the piece you wrote what and how much can you say?

Do you have the ability to look at a written melody and say whether it is good or bad without hearing it?If you do then how do you do that?

Given a melody which is bad,can you shape the melody to your liking without hearing it? 

Does the above abilities and awareness is essential for a good composer.By good I mean who can express his personal thoughts and feelings adequately enough for others to understand.

i don't think you know what "determinism" means, sorry

Realize some sort of idea -a complete one. Explore it.

By good I mean who can express his personal thoughts and feelings adequately enough for others to understand.

Not the best criterion for determining what a 'good' composer is.