Another vote for full, free and correct every flight. And always do it after the engine run-ups, just in case anything has been blown in to any hinges etc.
As Fuji says, trim is a bit more difficult. Despite nowadays having a sliding bubble canopy, I must admit I normally do the stabilator/trim check on the walk-around. A convenient check (having electric-only trim) involves two people but, failing that, I usually put the trim to neutral and check the stabilator movement against the markings on the fuselage, and then run the trim between extremes while standing outside the cockpit and looking at the tail assembly.
I haven't seen reversed trim but do recall being told off some years ago for writing up a defect when hiring a C152 from a flying school. The trim and indicator system had become partially disconnected and nearly full "nose-up" indication was required to keep the aircraft straight and level. Being a C152, the required yoke forces on take off were not great but there was a surprise element which may well have thrown a student. My cursory check of the elevator and trim had clearly been inadequate.