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I've used it, made some gates (up to DFF complexity) on a 180nm CMOS flow (shuttling back & forth from / to Cadence via GDSII). There's nothing unique about klayout, it's just a nice layout editor.
What you probably want, is material about how to design standard cells such that they are routable yet compact. That's not really layout-tool-specific, although P&R tools may inform how you like to place pins, row height, interior routing channels and compatibility with routing grid (if any), target features for router and so on.