It's good to realise that not every emergency is a failed power unit. Try some of these in the circuit (with an instructor if you feel you need a little advice)
1) Try flying a circuit with a stuck throttle (ie full or partial power).
2) Fly a circuit with failed ailerons or failed elevator, or both.
3) Trim cable has snapped. Leaving the aircraft in full nose down/up trim.
4) Imagine that you had a massive puncture on rotate and need to land a much as possible on the good wheel.
5) You engine has just chucked a large amount of oil on the windscreen. Perform a landing using only the DV window (probably best get an instructor to act as safety pilot).
Knowing that you can deal with all kinds of emergencies, not just engine failures, will certainly make you a better , if not more cautious pilot.