I'm not an absolute beginner, I suppose, but I an a fairly recent starter. I ran across Lonergan in some comments that were written on an essay of mine by the marker a few years ago. It took me a while to pluck up the courage to tackle Insight, and I got on with it quite well until about Chapter 14.
Since then I've read Terry Tekippe's two books - What is Longeran up to in Insight? and An Introductory Guide to Insight which were both very useful, and I am about to launch forth on Method in Theology.
As for application, I work in Education and the possibilities seem vast, as well as for explaining where the organisation I work for goes wrong much of the time.