The word magnify is often used to describe our efforts in our callings. At first hearing, it almost sounds like we are to draw attention to ourselves or to what we do as part of our calling. I suggest a rendering that is subtly different, being somewhat inverted.
For instance, there are things all around us that go unnoticed, and for different reasons. For instance, how people around us are feeling is often overlooked, because we miss cues, fail to infer circumstances from recent happenings, or simply haven't asked for their feelings. Commonplace objects, when optically magnified reveal complex and interesting structures and compositions that otherwise go unnoticed.
So, one way to think about magnifying our calling would be to do things that allow us to pay attention to things that would otherwise be missed, but that are important. Magnifying our calling may well mean magnifying the people within our sphere of influence and their situations relative to our calling so we can meet their needs, rather than ignore them.
Your obligation is as serious in your sphere of responsibility as is my obligation in my sphere. No calling in this church is small or of little consequence. All of us in the pursuit of our duty touch the lives of others.