4x12x12 is just about as perfect an anvil as you could ask for, and certainly better than what they had back when they made the Mastermyr treasure or Sutton Hoo Hoard.
You don't need a horn, hardy hole or pritchel hole on the anvil, and many an anvil never had them. The pritchel hole, for example only became commonplace after about 1820.
Every hardy tool works perfectly well when mounted in the vise.
Repetition is what builds skill. Cut a 20' bar of 1/2" square into 4" segments. Put a taper on every one of them, focusing doing the best you can. Don't do anything else. Don't jump around from one thing to the next thinking that you're learning as you go because you're actually hampering the learning process.
Do the tapers whether you like it or not, and you'll find that your last taper will be measurably better than the first because you've slowly drilled that skill into the mind and muscle. Then you get to go back through the pile and fix the early ones.
With all that done, now you get to do the other end, maybe making a flat round finial with half-faced blows on the near side of your anvil. Again, it's about focusing on the shape and getting everything right. Once you shape all those pieces, you'll again see that your first wasn't nearly good as your last. Repetition pays off.
What you're left with is the beginning of a coat hook or bottle opener, or trivets, or sundial..... really open to your design abilities.
The key is to do each step before progressing to the next. Don't make each hook start-to-finish.