Use vital actions and learn and understand why
That's what my instructor taught me, and great advice too. I've memorised the in-flight checks (and most of the other ones too, particularly the "oil pressure rise within 30 secs" stuff!) and rehearse them regularly (my poor wife is sick of them) - I guess my question was more "what sort of things do you all make a point of checking at different stages in flight?"
know what the minimum staic RPM limit is
in cruise make a note of the exact position of all the engine guages
Great suggestions - thanks! Any other ideas?