What is involved in being an incarnation? That's a union of different natures--which isn't a very useful definition. Maybe something operational...
The actions of the body have a purpose that isn't determined by the body's environment and reactions. The body expresses some aspects of the soul--and makes that expression possible.
Clearly this expression can happen through actions. But can the body express purpose or meaning through inaction? Through "just being," or "just being" in a way that is apparently determined by the body's environment and reactions?
That sounds kind of Zen, doesn't it? "Before enlightenment, chop wood, carry water. After enlightenment, chop wood, carry water.". Undoubtedly the body is having an effect on the soul, but it isn't obviously an expression of the soul through the body.
Despite a more amazing incarnation, Jesus had about 20 "dark years" about which we know nothing directly, though we can infer from his townsfolk's reactions that nothing dramatic happened. Of course, people can get used to pretty nearly anything, and a perfect carpenter who doesn't preach might be easy to get used to and ignore. Or maybe not--but their reaction tells me they weren't expecting anything unusual.
"Do little things with great love?" Maybe that's the answer to the "just being" question: doing the "reactive" ordinary thing consciously with love. Who sees the difference? Maybe just God.
Trying to be intentional about each action tends to pull my attention away from God, so I'm not persuaded that that is a useful exercise by itself.
If I have the Holy Spirit in me, what I do and am needs to somehow incarnate that. Pew-warming is probably not the most expressive way. Study ought to reshape my mind and heart, but somehow that still doesn't quite seem fully expressive either. Maybe the best approach is concentrating on doing one thing (with love) at a time, and letting everything else be reactive. Start small. As distractible as I am, that's hard enough.