Swamp,
All the stuff above is good advice. Just to touch on your grinding question, though. First, be sure to understand the basics leading up to grinding... center line and making a platform and angle of strike. Once you have your platform, the idea of griding is not so much litterally grinding the platform. All it really means it to sand it with a sand stone so it is not smooth. This gives the hammerstone, bopper or flaker a place to grab. Basically a rough edge contacting a rough edge. Otherwise the blow is contacting a smooth surface and instead of grabbing the stone and ripping a flake off, the blow just slides and fractures or powders the edge. This leads to step fractures or crushed edges. If all is well in the prep... good centerline, platform, grind and angle of blow, that is were you get the flake. Other stuff such as contour of the rock... how you hold your mouth
, yada, yada, yada... come into play, but those are the basics and hopefully answers your question about "grinding". Now, if you are like me, have a tendency to get lazy. I find myself trying to take a flake off without grinding and almost every time I end up with a crushed edge. I know it, I do it anyway and cuss myself every time. Some of us old dogs are just stubburn like that.