If you haven't come across it yet one of our moderators (ApochPiQ) recently posted a journal entry that I think might be relevant: Become a Good Programmer in Six Really Hard Steps.

[size="1"]EDIT: Just realised you actually mentioned this article in the original post -- my apologies, but I'll leave the link here for the benefit of anyone else reading the topic.
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Don't let the article scare you off however; the steps listed generally take a long time, and they're not easy to achieve, but it's not all rough-going with no reward along the way -- as you learn you'll experience a lot of rewarding moments where you manage to solve problems, where things click and you understand things you didn't before, and you'll probably make at least one or two pieces of software that you're really proud of and/or which help you out a lot in your day-to-day life.




If you feel you're getting beyond beginner books I'll second the recommendation of finding some more advanced books covering algorithms and/or data structures, or you could consider looking for a book which takes a more in-depth look at a particular subject (AI, graphics programming, whatever) which interests you. Don't be afraid to go back to your beginner books if you find you've bitten off more than you can chew, and don't be afraid to use reference materials. The important thing is to continue writing code and not to get too hung up on trying to do everything correctly the first time around -- just work towards making things work, and you'll find that the mistakes you make along the way will be your most valuable learning experience; you'll also get a feel for what works well, what doesn't work so well, and when/where it's worth putting in the effort to optimise.




You should also put in the time to learn how to use your tools properly.
Get really familiar with your debugger and the various functionality it provides; if you're new to using the debugger get some relatively simple (but bigger than "Hello World" -- you'll need enough to play with!) that you're familiar with and mess it up on purpose -- cause compile errors and learn how to efficiently look up the error messages -- cause logical errors and learn how to step through your code and examine the contents of your variables and track down where things are going wrong.
Find a profiler and learn how to use it -- until you're working with real code this probably won't click with you, but it's worth trying to start early so you can get familiar with the tools and get into the habit of checking which parts of the program could really benefit from optimisation.
Learn how to use some sort of source control -- get some different advice (there should be plenty of posts and articles on the topic) on different ways to use source control and try them out with your small projects so that you can learn different work-flows and figure out what works for you.


Hope some of the helps!