First, I'd like to follow tilly in recommending Code Complete and The Pragmatic Programmer. (As an aside, I wrote a little script that spits out a random tip from the Pragmatic Programmer book, much like the fortune program.)

That said, in my personal practice I strongly believe in these productivity boosters:

• Use whiteboards. Learn to analyze and design in a team.
• Use one good editor (emacs or vi) very well. Learn it. Extend it. Use it all the time. Use regular expressions to do repetitive editing tasks. Filter your text through perl programs. Etc.
• Use code generators. Perl is the perfect tool for this. E.g., generate the SQL for a database structure and the client code to access the database from a common meta-language.
• Use other well known UNIX productivity booster tools like make, expect, etc.
• Use version management (e.g., cvs) all the time.
• Never use copy and paste. Instead, automate the needed editing task using Perl or your favorite editor.

Christian Lemburg
Brainbench MVP for Perl
http://www.brainbench.com