can you find a copy of Beraneks green book, the big fat one? It has an excellent section on sharpening and what to look for.
as has been said before:
-stable platform. For me, a bench vise is favorite, but a stump, tailgate, etc is fine.
-correct size file.
-correct and consistent angle. Use the little hash mark on the back of the cutter tooth as a guide.
-be sure and use a straight push, with gentle upward and backward pressure. No see-sawing or scrubbing back and forth.
-if you like, rotate the file counter clockwise as you file.
-you should pay close attention to the corners of the cutter tooth, looking straight down on the cutter.
-all the shiny metal should appear under the cutter tooth and not down in the gullet.
-use a raker gauge.
personally, I can't stand the reduced kickback chain. Also, I feel that a round file chain is the best design for all around use. We cut limbs, stumps, buck logs on asphalt, etc.
Practice!