I cannot emphasize this enough. Listen to hearts, this setting is were you'll get some interesting variations. Same goes for lungs. Take BP's and if they are willing practice taking BP's on a leg. What about all those meds? What do they do, what are they for, what are their SE's. When a doc comes in to do their rounds, ask if you can follow them around. Review a patient's file and look at their blood work, do you see the correlation.
Even if you can't do this, just by asking shows your interest in wanting to learn everything. Geri is an important sub specialty, so much so, specialty leadership programs are being developed.
http://www.nursingsociety.org/LeadershipInstitute/GeriatricAcademy/Pages/GeriatricAcademy.aspx