After repeated threats to my physical wellbeing and a bit of wheedling by rocketscientist2105, i was finally persuaded to put a link to his orangeboard.
Step 1: Select the Steel
Tools are made from hard steel, right? They usually are.
If the tool you're using has to put up with a lot of bending and twisting and hammering and general abuse, it'll probably be a meduim carbon steel, or a spring steel. Either of these is fine, in fact you could just use a bit of a car spring like jtobako did, that'll do the job perfectly, because throwing knives need to be flexible. If the tool you're using has to be hard and wear-resistant, like a file or a drill bit (I don't recommend using drill bits.) then it'll most likely be high carbon steel. I used a file. The first thing we need to think about when forging files is that they have teeth. Forge them with the teeth still on and you'll trap scale in the gaps, then fold the teeth over. it'll be terrible. Grind the teeth off the file. it helps if you anneal the steel before you do this. To anneal steel, get a good fire going and chuck the steel in. Let the whole piece get to a dull red heat and then let the fire die off slowly. If you anneal the file, you won't wear away your grinding wheel too quickly.