Having a good quality piano action is essential if you are to develop a good piano technique.
Let's start by looking at the feel and response of the keys. Every time you press a key on an acoustic piano, a hammer strikes a string causing the string to vibrate and sound a note. The hammer is connected to the key by a series of levers which gives a natural weight and feeling of resistance each time you press a key.
So how does a digital piano effectively simulate this weight and resistance?
Keyboards and synths use a spring loaded key action where a spring at the back of the key ensures the key returns to the up position. Entry level digital pianos use a similar action but with the addition of a small weight added to each key. This is known as a semi-weighted action and is fine for players who don't want the fully weighted action of an acoustic piano.
A hammer action keyboard uses actual hammers that rise when a key is struck and fall back under their own weight. This offers a much more realistic feel.
Better still is a progressive hammer action keyboard where the feel of the keys gets slightly heavier as you move down the keyboard. This is because the strings on an acoustic grand piano are shorter and narrow in the treble section and get progressively thicker and longer in the bass section.
Digital piano keys are usually made of plastic but in some cases are made of wood. Some will argue that a wooden key is more realistic but, as long as the weight or mass of the key gives the same resistance as that of an acoustic piano, it shouldn't matter what it's made of.
It is important to point out that there is no right or correct touch to simulate as not all acoustic pianos feel the same. For example, a grand piano is usually lighter in touch than an upright piano, and even uprights from the same manufacturer can vary. It is what you feel most comfortable playing that is the most important factor.
Most pianos will have three pedals, the most important of which is the one on the right, called the damper pedal. When we release a key, the sound ends abruptly which makes it impossible to join two notes situated far apart. That's where the damper pedal comes in as it allows the notes to sustain or carry on sounding after your fingers release the key, which is why it is often called the sustain pedal.
On some basic digital piano models, the damper pedal is basically either on or off. But on an acoustic piano it is possible to partially engage the sustain pedal so that the dampers touch the strings very slightly. This technique is called half pedalling and gives a pianist greater control of the sustained sound. Some digital pianos can successfully recreate this effect using a technology called Progressive Damper Action.
The outside left pedal softens both the tone and volume of the sound which is why it is known as the soft pedal and the middle pedal is known as the sostenuto pedal which sustains only the notes that you're playing when you press the pedal down. For example, you can play a big bass note, put the middle pedal down, and then doodle some stuff over the top with the bass note sounding throughout.