If I could change one thing about how most self-taught adults play, it would not be their reading, their rhythm, or their repertoire. It would be the shape of their hand.
Hand position sounds like a beginner formality — something to get past on the way to real playing. It isn't. It's the mechanism through which every note you will ever play gets its sound.
The shape: hold an invisible apple
Let your arm hang loose at your side. Notice what your hand does on its own: the fingers curve gently, the palm stays open, nothing is stretched or clenched. That relaxed curve is the hand you want at the piano.
The image I give my students is to imagine holding a small apple, or a ball, in your palm. The palm stays domed. The fingers stay curved. You press each key with the tip of the finger, not the flat pad.
Your wrist stays level with your hand — not collapsed below the keys, not hitched up above them. Your forearm, wrist and knuckles should form a comfortable line.
Why the curve changes the sound
This isn't aesthetics. There are three concrete reasons.
Control of tone. A curved finger transmits the weight of your arm directly down into the key. That gives you a full, singing sound and — crucially — lets you choose how loud each note is. Flat fingers slap the key surface; the sound comes out shallow and uneven, and dynamics become hard to control.
Speed. A curved finger only has to move a short distance to strike. A flat, extended finger has to travel further and drag more of its length. When you later want to play something quick, that difference is the difference between clean and muddy.
Your hands' health. This is the one adults ignore until it's a problem. A collapsed wrist and flat, straining fingers put load on tendons that were not designed to take it. Playing should never hurt. If it does, the position is wrong — stop and reset rather than pushing through.
Two things quietly working against you
Long fingernails. They physically prevent the curve: to avoid the nail hitting the key, you flatten the finger. There's an easy test — if you hear clicking on the keys, they're too long. Keep them short. Every professional pianist does.
Seat height and distance. Sit at the middle of the keyboard, far enough back that your elbows have room to move and sit at roughly the height of the keys. Too close and your wrists collapse; too low and you'll compensate by flattening. Hand position problems are often really seating problems.
Fix it in one session
Before you play anything, do this warm-up — it's the one I open my first lesson with:
Rub your palms together until they're warm. Make a tight fist, then snap all five fingers open. Repeat five times. This brings blood to the hands and releases the tension most adults carry from typing all day.
Then put your right thumb on middle C, one finger per key: C–D–E–F–G. Play up and back down, slowly, and watch your hand rather than the music. Is the palm still domed? Are you landing on fingertips? Is the wrist level? Correct it every time it collapses.
Five focused minutes of this daily will retrain the shape within a couple of weeks. And unlike most things in piano, this one produces an audible improvement almost immediately — the tone gets rounder.
Why I insist on this so early
Technique isn't something you add later, once the "fun part" is going. It's the foundation the fun part stands on. Habits formed in your first months are the ones you'll be fighting in year three — and un-learning a collapsed hand is far harder than learning a good one from the start.
That's the difference between learning shortcuts and learning properly. Take the extra week now; it saves you a year later.