Very nice, a good outline of a free alternative to Photoshop for doing some of the basic functions that people need to use most frequently.
The best tip you can get is to follow the Picture Taking tutorials by Pugwash and try and illiminate most of the errors in the photo when taking it instead of relying on software, but if all else fails Photoshop and other software are excellent tools, and a must have for high wuality results, it's the little things that make the big difference.
Chris