When people begin blacksmithing they typically begin with making a clothing hook because it is simple, practical, and it looks nice. However, I believe that arrowheads are much simpler to make. While arrowheads may not be as practical as hooks, they are way cooler, and let's be honest, most people interested in blacksmithing are looking to make swords, arrows, and other stereotypical medieval things. Medieval arrowheads or socketed arrowheads are very simple to make, and with practice, they can be made in under 15 minutes. All you need is a scrap piece of rebar, a forge (or simply a fire), and an anvil (or something acting as one).
To start, you need to upset one end of the rebar to make it wider; this will help you to more easily form the socket. Once your metal has reached an orangeish glow, hold it above the anvil and strike the rebar into the anvil. Holding it above the anvil and striking into the anvil will help to prevent the rebar from bending. Once one end is upset, just begin to hammer it flat. This is called fishtailing because when completely flat, it will resemble a fishtail. At this point, all you will have made is a spoon.
Next, you need to begin rounding the fishtail to form the socket. Start at the top of the fishtail so the socket forms more of a cone rather than a cylinder. After you form your cone, you will need to make sure the arrowhead is flush and round. For more uniform arrowheads you can use a socket mandrel, which will allow you to shape all your arrowhead sockets to the same size. When your socket is flush with the rebar, you can then cut it, typically an inch above the top of the socket. This can be done with a grinder, or an ax head to heat cut it.
From there, you only need to form the point; the simplest point is a bodkin. The bodkin point is essentially a practice tip. It doesn't have the same cutting ability as a broadhead, as it is basically a metal spike (great for piercing a knight's mail armor). There are many different forms and shapes of a bodkin arrowhead, so how you form it is completely up to you; there is no real wrong way. The first few you make may take a few hours, especially if you have problems heating it up in your forge; just take your time and keep working at it.