I’ve had this thing a year +, and still consider myself a “noob.”
That said, I have worked hard to integrate the OT into my workflow. I write music for TV as well as tracks for artists, and I find the OT to be a super inspiring breath of fresh air when my other composition sources have become stale.
I like to build patterns, and get my “song” to a place where I can switch between the patterns to get the structure going. Once I find myself making the same moves, I open up the arranger and commit to the order of things.
Sometimes I have to rely on my DAWs (Logic and ProTools) as I don’t really have any hardware synths. In these cases, I like to make a simple beat on the octatrack, I record it to my DAW, and build the bass/synths etc around it. Then I export the files (sometimes stems) back to the OT and create an arrangement (with changes and nuances to the beat, which I find easier to create with the other tracks crackin)
I’ve started creating sample chains of my favorite patches so I can build more of the initial idea in the OT. Obviously this only works for certain types of sounds. I have an iPad I play with sometimes, but speed is super important for me, and sometimes a crutch when it comes to experimenting. I’m sure i’m an experiment or two away from being able to rock all those apps with MIDI triggers and/or my midi keyboard. (anyone want to drop a tip to get me started there??)
Most of my work requires me to dump stems out of OT for alt versions, and also the flexibility to adjust the mix. This would be impossible without first arranging the patterns. Also, once you get into scenes, if you have a fader move you always do at the same spot, it’s worth recording it internally and triggering it later as a sample. (this comes in handy when making the stems I have to make.)
One of my favorite things about the OT is that they continue to develop the OS. Added features such as slice mode and chromatic are huge, and moved the unit from my closet back to my desk. (now please add the ability to merge projects!!) 
Read Merlin’s PDF if you haven’t already, it’s a nice angle on how to think of some of the workflow.