A correspondent asked this. As I haven't the time now to answer him, I'll invite The Collective to do so.
[Quality of C-coded Tcl/Tk source.]
[Read good code.]
[Paramount importance of engineering review.]
[Example rewrite sessions.]
[chat?]
While learning to write good (better) code is a life-long journey, I think that there are three significant events in my career.
First, while employed in a Fortune 100 company, my group all took training in structured design (the "Yourdon" methodology, FWIW). That taught me the importance of loose coupling, well defined interfaces, and code reviews.
Second, I had the good fortune to read "Software Tools" by Kernighan & Plauger [L1 ]. I regard this a possibly the single best source on software engineering.
Third, as part of my MS studies in Computer Science, I took a course on "provably correct systems". While I initially thought that the couse would be interesting, though abstract and useless, it may be the single course that has most influenced my coding style.
That said, I endorse reading good code and code reviews as important parts of the on-going process of learning to write better code.
-- [CLN]