Play pieces that you enjoy playing or pieces that you know well!
Never give up. The fingering, speed, and chords in some pieces may be frustrating and difficult, but push through it. If you get frustrated, step away from the piano for a few minutes until you are ready to play again.
The more you practice, the better you will perform.
You may like to accompany a singer on piano and perhaps form a rhythm section with other instruments.
Learn to sight read music. This will allow you to play a large range of pieces without learning them from memory. If you need help with sight reading, it is recommended that you try Fast Keys (a small game that greatly speeds up the learning process).
If you're at a recital and your hands shake wildly, sit on your hands for a few minutes before you go out to play. It calms them down.
Find the right teacher! Your relationship with your teacher can affect the way you feel about practicing, so arrange for a trial period of a few weeks to find out if there's a good fit. Parents, especially--pay attention!
If you are shy, practice playing in front of your family and friends. They will enjoy it and in time, so will you.
Learning music theory is fun and is the best way to become a great musician, whether you want to play classical, jazz or pop.
Always follow the fingering on the piece (although there are certain exceptions). While some of the finger positions may feel awkward at first, following them will help you play more smoothly because you won't have to adjust your hand position because you cannot reach the next note.
The exceptions on fingering are rare but important. Male and female hands have slightly different shapes with the length of the index and ring fingers being different. Also if your hands are small, some stretches simply aren't possible. However 95% of the time the printed fingering is right so persevere and it will make sense.
Practice sight reading; it's an important skill. It will help you master a piece faster and give you more time to work.
Hand and body posture are very important. Slouching gives a bad impression and having a bad hand posture will be counter-productive to your practice. Keep your wrists loose and your hands flexible. Keep your fingers at a natural curve, as if you were holding your hands at your side. This gives you more power in your finger strokes.
Listen to your notes and tune your ears to the keys' pitches. This is needed on some advanced piano tests and will allow you to impress your friends by playing blindfolded!
Don't be afraid to really hammer out those notes in that forticiticimo section (fff). Just make sure you don't slip on the notes. Put some passion into it! Any kind of music is worthy of your passion.
Do not keep your foot on the sustaining pedal; it blurs your chords together and makes them sound "muddy."
It is better to play too slowly than to play too fast when you are performing. Play evenly and with a great deal of care in your touch and you will sound professional.
Keep a regular, steady rhythm when you are playing. Just playing rhythmically makes a piece sound a lot better. Consider buying a metronome to help with this.
Play simple pieces by ear and make your own arrangements of them. This will help you to become less dependent on written music. When you are playing by ear, keep going! Do not start sections of the piece over again. If you miss a chord one time, you can practice so that you'll play it the next time. The main thing is to overcome repetition and hesitation and learn to play a piece through smoothly when you are performing it.
In addition to studying traditional chord relationships (harmony), take a class in composition and listen to as much music as you can. Community colleges offer excellent instruction in music theory, history, and composition. Playing with other people in ensembles is also an excellent idea.
Get used to the idea that some of the pianos you will be playing will not sound that good or be in perfect tune. This is one of the hazards of being a piano player--you can't carry your favorite instrument with you. Try to make the best of things when you are playing an inferior instrument. A good pianist can usually make a bad piano sound reasonably good--although some pianos are in such bad condition that you should feel free to say that you cannot play that piano.
If you want to correctly use the sustain pedal, play a chord, then before you play your next chord, quickly lift up the sustain pedal and put it back down. Whenever you change chords or play notes from a different chord, "reset" the sustain pedal.
For Medium/Advanced players, try playing through that new piece using the chords written above the grand staff. Use your left hand to play octaves and your right hand to play the chord. Start off using the first inversion of every chord, then for a challenge, limit yourself to using only one octave and trying out different inversions of chords.
Take shorts breaks every so often when practicing. This will allow your fingers to recover and your mind to become better focused.
Don't freak out when you can't play a measure (or two). Just take a short break. Give yourself some time to clam down before you attack the problem again.
For medium/advanced players, eventually, you will play faster pieces that are also long. If you keep pushing on the keys, you will tire out before you even finish the first page. To prevent this, lift your fingers up higher for louder notes and move your wrist so that it "follows the notes" (as the keys you press make higher and higher sounds, your wrist gets nearer and nearer to the right side of the piano when you're facing it. Do the opposite when the sounds made by the keys get lower and lower. However, if you overdo it, there'll be no point)
And curve your fingers for a stronger tone and a better quality of music. Resist the temptation of playing flat fingered.