Set a goal
Have a goal every time you sit down to practice playing scales and arpeggios over and over 'will not' improve your playing. A goal would be to master a chosen piece within a certain amount of time by practicing it for 15 minutes EVERY DAY. Then when it has been perfected, transposing it into another key.
Accompany a friend
Try to accompany a friend or play in a band. Playing with other people is THE BEST WAY to improve your rhythm. You have to really concentrate very hard to stay in time and this action alone will improve your rhythm, sight reading and musical ear like no other. It is also a lot of fun and breaks down the boredom of practicing alone.
Don't worry about making mistakes. If all we did was worry about making mistakes, we would never get anywhere. We would live in constant fear!
When you are learning a new piece of music for example. If you were to know in advance that you where going to make 25 mistakes before you could play the piece perfectly, would you worry about making these mistakes?… NO! You would want to make these 25 mistakes as quickly as possible… wouldn't you? What I am trying to say is each mistake you make brings you closer to your goal.
As long as your ear can recognize the mistakes, you can correct them and move on.
Learn How To Play Chords First
If you can learn the basic chords first before tackling classical pieces, you will be a long way ahead. Most popular music is based around simple chords and if you can master these, you will be able to play a lot of famous tunes and have great fun doing this.
The classical approach really limits you early on and I find that it discourages most beginners from continuing past their first year. If they were to learn the chord system first and then progress on to classical pieces, I am absolutely certain there would be far fewer students that give up.
The Right Mental Approach
Getting your mindset right is probably THE MOST IMPORTANT thing to do. Practicing because you have to and just going through the motions will not get you anywhere. This approach nearly always leads to boredom and eventually giving up.
The way to improve rapidly is to concentrate completely for every minute you set aside for practice and focus on improving one thing. This could be part of a piece, a new chord, a scale or anything you choose.
Seeing this progress gives you a sense of achievement and will keep you going through the session and the next.
Make Sure Your Mind Is Clear
If you have had a bad day, received some bad news, been in an argument etc. then you should not practice. You must get yourself in the right frame of mind in able to make the most out of your practice session.
Try going for a walk over the park – get some fresh air. Read a book, watch some TV – whatever it takes to get you in the right mood ready to practice and make some improvements to your playing.
If you still can't get yourself in the right mood then skip today's session and come back tomorrow focused.
Many sports coaches teach the skill of visualization. Athletes are taught to see themselves running and winning an event. They see themselves from the starting gun step-by-step all the way to the finish line, breaking the tape, arms in the air and the crowd applauding their victory.
When the race 'for real' comes around, they are mentally prepared and more likely to run to the best of their ability.
It is no different to playing the piano…
Try visualizing yourself playing a piece of music that you have been practicing recently or are about to perform.
Picture the piece of music in your mind, the fingering for each note, your fingers pressing down the piano keys, the hand positions and chord shapes. Try to hear the piece.
You will be amazed at how quickly your playing improves when you can visualize a piece in as much detail as this.
For instance, if I am having a hard time, physically or mentally, an hour of piano practice is the best remedy for me as it completely blocks any extraneous thoughts and feelings.
Practising the same thing every day. I personally make most progress if I practice the same thing every other day.
Playing with other people? I am sure it can be very useful for most people but it does not suit everybody's temperament .
The classical approach limits you early on? Again it depends on the person learning and what they want to play (and the way their teacher goes about his/her job)
I agree about no 5, but would suggest delving into all sorts of pieces for fun beside the set practice pieces.