This is sound advice. The technical side of things is important, but do not focus on it myopically. As you are no-doubt already relatively strong technically, it may be worth making a little time to improve your understanding of the business, improve your negotiating skills, etc.

Another useful skill is the art of software project estimation: see e.g. _Estimation Games_ [1] by Rob Thomsett, or Dadhacker's _Keeping Sharp_ [2].

[1] http://www.thomsett.com.au/library/item/estimation-games

[2] http://www.dadhacker.com/blog/?p=2267