Hi James,
I go along with what Brian has said. You can learn a lot from Registrations others have used. For example, I really like the idea of using a 'percussive' instrument like a 'piano' or 'vibraphone' along with a 'continuous sound' like 'strings' or a 'choir'. Pete Walker has done this in his recording of "Love Me With All Your Heart". Click the below to hear his combination of voices:
Do a right-click to open this up in a New TabPete Walker - Love Me With All Your Heart DEMOPete says:
I played the chords and right hand on multi tracks one and two live and played the counter string section on track three, then played them together.
To answer your original question, I always have in my head the sort of sound I am trying to get for a particular song so will spend quite a bit of time setting something up. And sometimes I don't actually know what I want until I find it. Also, on my AR I am unlikely to find an existing Style I am happy with, so spend time 'tweaking' styles and adding 'PARTS'. So I spend more time 'tweaking' sounds and styles than I do actually playing, which would horrify most people who play a keyboard. But I enjoy doing it, and get a great deal of satisfaction when I get what I am looking for.
Here's an example of a 'percussive' sound together with a 'continuous' sound; in this case piano with 'organ flutes' playing quietly in the background (no Style involved here).
I'll Walk Alone / Mistakes / Nice To Know You Care / DreamDo a right-click to open this up in a New Tabhttps://app.box.com/s/2xm3qbsjonw6emrzhexmtn3zmo22vix9And here's an example of where I have 'tweaked' the Style to get what I wanted. I have DELETED the original Bass PART and put in one of my own; and put in the 'Ooh, Ooh - AAh, Aah' PART you can hear in the background.
Good Luck CharmDo a right-click to open this up in a New Tabhttps://app.box.com/s/1ljbsof816bxitumjq4n2d7hkyh37qukEverything I play has had something 'tweaked', and as I said, I probably spend too much of my time doing this sort of thing. (And too much of my time on this Forum!)
Hugh