This thesis focuses on different aspects of radio pulsars: on the one hand it describes research on the pulsar emission mechanism (nulling, drifting subpulses, single-pulse polarisation and their mutual interaction). On the other it gives an account of investigations into the evolution of the pulsar population as a whole (birthrates, velocities, magnetic field evolution) and possible ways to probe this population (simulations of upcoming pulsar surveys). In Chapters 1-3 we investigate observationally how subpulse drift behaves after the 'nulls' (stops of all emission) that some pulsars show. We find that the drifting-nulling interaction tells much about the true motion of the sparks; the spread in the inferred velocities of the sparks is much larger than previously thought possible. In Chapters 4-6 we study the interaction of drifting subpulses, refraction and polarisation. We show how refraction changes subpulse patterns (Chapter 4); we find that the large polarisation-angle changes observed within single subpulses can be explained in terms of orthogonal polarisation modes (Chapter 5); and we demonstrate that, in contrast to the handedness, the amount of circular polarisation in pulse profiles is independent of frequency (Chapter 6). In Chapter 7 we focus on pulsar evolution, and show that magnetic field decay is not needed to explain the observed relative lack of long-period pulsars; furthermore, we find that the scarcity of high-field radio pulsars does not have to mean that high-field pulsars ('magnetars') do not emit in radio: even if many are born, their evolution is so fast that only few, if any, are visible at a given time. In Chapter 8 we extend this population synthesis to LOFAR. We simulate and compare strategies for finding new pulsars and find that a 60-day all-sky survey can find 1500 new radio pulsars, doubling the currently known population.