I work differently depending on the track type. However the first thing for me is hearing a theme in my mind. It's then a matter of recreating that theme onto the midi track. Which personally I do too by clicking in the piano roll.
I start off by loading the suitable template which I've created. I have a selection of Strings and Brass (which I tend to use for hybrid orchestration). Strings, Brass and woodwinds (for a base point with alternative percussion) or Strings, Brass, woodwinds and orchestral percussion (for a more classical setup). These are big templates, and can take me a day or so each just to set them up by time i separate them into their midi's, groups, their automation velocities and effects channel. But it means when I feel inspired, or I hear that theme I load up the relative template to the type of composition.
Loading up Kontakt predetermined samples as most of us know load much quicker than reloading them all one by one. Waiting 5mins for a complete setup is worth the days work imo. These templates get worked everytime I get some new which I consider better for the template. Which tends to be every 6 months to a year and I'm due to sit and make a new setup coming this FLStudio 64 bit upgrade as bridging wont be needed.
The orchestration is then a matter of putting what I have in the piano roll, adjusting the velocities and (only now) automating the instruments one by one for the best possible sound. Previously Automation wasn't possible as it would stutter my PC causing it not to work (due to the crap hardware). My head is actually the best weapon I have, hearing what I want before it's even created means that I'll strive to get the closest thing possible. I find electric/synths etc really hard as those things can sound amazing in my mind, yet so hard to create to the sound I want. Settling most of the time or losing track and opting for another, whereas I find orchestral instruments more predictable. I know what they should sound like, and I know what I should strive for.
To me a theme has to be present in my orchestrations, whether this be literal or through a genre either I find works. I do have an Keystation es61 keyboard. I very rarely touch it though out of laziness and lack of keyboard skills which I lost of the last 15years.
I'm looking for midi controllers though to help automate instruments so I can assign CC's to them instead of clicking and dragging every little dot. Ive seen some small ones, anyone got anything like that?