While I don't do a lot of "trance" music...I've done similar stuff way back when I was really into the MIDI/sequencing thing back in the early '90s.
IMO...it's no different than any other type of music. As you mentioned, everyone has their work SOP, but I think it's safe to say most people will start with the rhythm AFA getting tracks down...though of course, you probably need to have some idea of the structure/melody in your head.
If you are just trying to piece anything together and then see how it comes out...yeah, that's also a way of doing it, but it will take a bit more work than if you have some of the song already in your head.
Focus on getting the drums/rhythm going, and then add some basic simple tracks that contain the essence of the melody and arrangement....then start layering tracks.
Once you get something going, you can always go back and improve/embellish on the initial melodic direction.
I think with trance...it's about having one or two or three central "themes"...and then off of them, do smaller/shorter themes, but you keep coming back the central themes or have them always threaded throughout.
That's what gives you that trance vibe...both the repetition of the central theme and the evolution of side themes.
Let you imagination go wild...
There's a few guys here who do a lot of electronic/trance kind of stuff. Kcearl is one of them I know of, as he's posted some nice electronic compositions in the past.
I'm sure some of them will drop in and give you more detailed suggestions.