First hammer advice, since this comes up every winter when folks get bored. Pick steel you can actually work. A leaf spring or a chunk of 1045 from the scrap pile will teach you more than fancy alloy steel that fights you the whole way. Drift the eye early and often, and flip the head over constantly while forging so both cheeks stay even. Mine came out lopsided the first time becuase I kept only checking one side.
Don't stress too much over the finish. A hammer with visible hammer marks works exactly the same as a pretty one. What matters is that the face is flat, the peen is centered, and the handle fits your grip. File the handle till it feels right in your hand, not untill it looks like a catalog photo.
On hardening, keep it simple. Heat to non-magnetic, quench in oil or water depending on your steel, then temper in a kitchen oven at a modest heat for a couple hours. If a file still bites hard into the face, you're fine. A chipped face from skipping the temper is a far worse day than a slightly soft one.
Make two. You'll want the second one anyway.