While I am far from an expert Knapper, here are a few things I have learned from my forays into the lithic arts:

1. Always wear eye protection.
A good deal of what we know about the process of making Lithic Points was learned from a man known as Ishi. One of the techniques learned was Ishi's method of removing a flake of stone from his eye. Upon realizing that he had a shard in his eye, Ishi would stop what he was doing, and pulling his eyelid away from the eyeball, he would strike himself sharply in the back of the head. One of the anthropologists he spent his final years with tried it and claimed he wasn’t sure if it actually dislodged the stone, but it certainly made him tear up, which did the trick anyway. Personally, I’ll just wear some damn goggles.

2. Read everything you can.
I would recommend Flintknapping: Making and Understanding Stone Tools by John C. Whittaker. This has been my principal guide, and an invaluable one at that. The web is also a good resource, both for information and to find places to buy Knappable material.

3. Be resourceful.
You don’t have to live near an obsidian deposit to get into this. You don’t even have to order stone over the Internet. I once made an entire year’s worth of Christmas gifts out of an old brick of architectural glass and some Bamboo from the back yard. Hell, you can even use some types of porcelain. It’s (euphemistically) called Johnstone.

4. You don’t have to use traditional tools.
A lot of people prefer copper to antler. Me, I use aluminum and a Big Honk’in Rock.

5. Do it somewhere you can clean up after.
Kinda by definition, Knapping will result in an area littered with tiny bits of razor sharp stone. This is not a good place to let the cat play.

6. Gloves are your friend.
Once again, you will not believe how damn sharp this stuff gets. Wear a good pair of leather work gloves. Always. I once screwed up picking up a point and sliced off a callous from my palm. The cut was so clean and effortless that it did not bleed. You don’t know how disturbing this really is until you hold an inch-long flap of your own hide in your hand.

7. Read everything you can.
Its important.

This is in no way meant to be exhaustive. I just saw that the Flint Knapping node was pretty barren, so I figured I’d throw in my $0.02. If I did anything wrong here, let me know. It’s my first writeup, so go easy on the noob.