Hi,
That's a good question.
To write good code, I think the knowledge of the language is more important
than the use of the API (which is pretty simple).
Study well known apps written with GTK+. Learn from the pros.
This is Open-Source power. Also look carefully at examples apps given with
GTK+ and cleverly separated from the API reference.
Browse forums and mailing lists you can learn a lot of things from other programmers.
Confront your code to their opinion. If they say nothing it's good. If they say
it's good it's excellent. If they say it's crap they'll say how to improve it.
Regards,
Katsankat