I do pretty much the same as randyris (above). The technique seems to work well and I think the double sanding with each grit (radial and longitudinal) makes all the difference.
Only things I can offer extra are that even though Tru-Stone seems hard, it can be easily oversanded, so be careful when wet sanding (watch out for a thick slurry). Use a light touch and a slow speed. Also, be REAL careful to avoid cross contamination with your various grits (clean water, separate wiping cloths, etc).