Just a couple of things. First the type of stone is not all that important how you use it is. Personally I use a diamond dust stone in 320 grit and finish with a good steel. Arkansas oil stones(Buck for instance) are also excellent. Holding a constant angle is critical to getting a good edge, until you learn to do it by eye try a knife sharpening jig. It holds the blade at the correct angle. For a real edge I always finish with a steel. in fact that is all I use most of the time. A very good knife steel can be made by taking a 10 inch mill file and grinding the edges rounded on a grinding wheel, use a fine wheel and stroke the file lengthwise along the wheel, Using just the edge it will put a razor sharp edge on a good knife. My test for a useable edge is if it will shave the hair on my arm clean. After a day of sharpening my knives my left arm looks kinda patchy.
