American Institute of Physics has a review of the past 75 years of developments in physics and a projection to future trends. They see at least two obvious paths forward.
1) There are deep unknowns in the fundamental nature of matter. We can hope for insights into both fundamental particles and cosmology, with unforeseeable uses.
2) We can go much farther in straightforward understanding and manipulation of the immediate material world. Useful new capabilities are expected with improved understanding and mastery of the physics of condensed matter, and beyond in the realms of nanophysics and biophysics.
What about advances that we can’t predict? In the past we have seen many unanticipated discoveries. And most of them—from lasers to dark matter, from medical physics to climate change—depended on new instrumentation (including computers) and extensive observational programs. Today’s student should pay special attention to new developments in instrumentation and collaborative organization.