Once I'd set up this 'virtual orchestra' on my synths, I saved the setup and used the exact same setup for all the Phoenix music, to provide some consistency in the sound. (Although there are a few exceptions, because we ended up also using some of the very early stuff that I did before I had mapped out the instruments properly.)

Next, I tried to put some work into getting each instrument's 'phrasing' right. Again, I didn't go overboard and learn every technique of every type of violin and all that - which I really should have done, but you've got to draw the line somewhere. So I just tried to use a bit of common sense and use the instruments more or less in the way that I figured they would be used in an orchestra. For example, to play a string-chord, you don't just slap 4 fingers on the keyboard - you split the chord and chord progressions into basses, celli, viola and violins and make them create chords and harmonies between them.