I always find more difficult to write music for an orchestra, or for an ensemble without particular soloists.
If I am writing chamber music for specific players, then it makes it easier to start writing.
This is not just because I am able to write for a player's specific talents as an instrumentalist, but I can draw on my knowledge about the person behind the instrument.

However, this is an orchestral piece.
I found a way to write personally though: I decided to place the instruments in particular orders on stage to characterize the orchestra.
They are divided in to 3 groups: Right, Centre, and Left.

Right and Left are identical apart from on the right there is a piano, and on the left there is a harp.

In the centre the low strings and brass sit in front of the conductor.
The higher registered instruments, two groups of violins, violas, flute, oboe, clarinet, trumpet and percussion, sit behind and above them.

This forces me to compose in a particular way.
For example, the central strings, 2 groups of violins and viola sits far back, but higher place on stage, they act as “spine” of the piece.
They are almost always calm and holding, usually the closed high pitched chords played often with harmonics even whatever the events are happening around them.
It is a little bit like Sho which is mouth organ in Gagaku, the Japanese traditional instrumental group (the world oldest orchestra).
Although usually Japanese Gagaku music, everything else also moves slowly.
I wanted to make complete opposite to that, since the spine is there, so the surroundings, which Left, Right and heaviercentral-front instruments can play sometimes sudden, other times quite busy sections.

These groups play different “roles” at the same time but gradually start to play together by the piece progresses.
Occasionally there are quite violent Pizzicatos played across the orchestra (in my imagination these are like “rain”, but more violent, more painful, “hail” perhaps?), for example from Left, Centre and to Right strings, that I edited in the piece after I finished the first draft.
This is to state the all those “roles” have very different personalities but they are in the same “scene”.

About half way through the piece, the Sho-strings (central-back violins and violas) start to free themselves up.
Finally they start to play the main role, have a lot of lines played together, although solo violins and violas from Right and Left group plays by the side (for me, “these lines are leaking”to Right and Left groups) leading into the last section which is at last the orchestra plays as “one group”.

These were the initial ideas and my first draft of the piece.
I usually take a week off since the completion of this, and then I forget everything about the “initial idea” and start editing the piece like the movie-editor would do.
Therefore, this abstract-story was there very clearly from beginning to end at the first draft, but then I cut some sections, mutate them and insert into more forward (like the opposite of the “flashback”) or layering on top of them to make the piece more maybe unpredictable. I always like to compose this way, I feel I can destroy it after I know what it is all about, even everything including the initial ideas are very abstract visions/stories.