Hi Karl!
As I'm a little bit mad I use the same technique as you: following the panel lines with a "three haired" brush! It's very long but you have "clean" panel lines.
The technique Graham is reffering to is far more easier and also very effective. BUT works best on previously coatted kits (future) and with oil paints!
DO NOT apply this technique on mat paint with an acrylic wash for example! It would ruin your work! Acrylics dry to fast and they will leave traces! Oil is perfect because it dries slowly!
As Graham said before, PRACTICE is the magic word and NEVER test on a current project!
Jean-Luc