How would I go about teaching myself how to sight read for piano, should I practice out of a sight reading book? Or should I take a piece of music with a lower grade level (such as Bach) and sight read that?
The important thing is that you choose music which is technically simple enough to fully comprehend immediately. This means music that would otherwise be well below your level. Bach is quite complex, and is hard for even advanced players to sight read. I don't know where this idea that Bach is simple came from, and it's seriously misleading.
Look into music of the Classical and early Romantic periods, such as Clementi, Haydn, some Mozart, and portions of Beethoven (his sonatas #19 and #20 are very easy, and there are easy movements of most of the rest).
I taught myself to sight-read music by remembering the whole process of how I learned to read out of books in school. I started with simple words that I already knew and understood and worked on recognition of those words on sight and using those words in phrases that made sense. After working on it for awhile, I could see the word and hear that word being said in my brain. It's much the same experience for me when I learned to sight read. I practice reading until recognition becomes automatic and I can hear the sound of the note in my brain. Just like learning songs, the process is slow at first and tests one's patience, but then the pace usually picks up and soon enough reading becomes easier. After a while you might even be able to know how a song goes without ever actually hearing it anywhere except in your head. I am a pretty good sight reader now but I still work on it because there are things I don't recognize as easily as others, and I'd like more speed and fluidity. Also I combine my sight reading with practicing scales and melodic patterns and it goes a long way towards tying everything together for me.
The process is simple, though not easy:
- Select a piece that's just above your current ability to read easily, one that makes your brain work.
- Set a metronome to an easy tempo (this is the crucial step. A metronome will reveal all kinds of hidden tendencies and paradoxically help you relax since it relieves you of the responsibility of staying solid in tempo.)
- Play only the first beat of each measure. Then the first and third beat of each measure (assuming 4/4 time).
- Fill in notes as desired.
- Forgive yourself for mistakes, just keep moving.
I think it's actually quite unimportant how you learn sight-reading, what is important is that you do it – practice frequently! So, use whatever music you like to play, which adds incentive for that.
Once you have the basics right you should also make sure to get acquainted with unusual key signatures or whatever that may not be found in the music you'd choose to listen.
Bach is definitely a good source.
Play whatever you can play easily – it's ok practice, but this is not the most important thing in sight-reading.
The first key to sight-reading is training yourself to ignore your mistakes and keep a steady tempo at all costs. Usually this means lowering the tempo, and gradually raising it over the course of a single piece, and many pieces in the long run.
Secondly – and theoretically – sight-reading is about recognition of common patterns that are found in music. For example, it is almost impossible to sight-read many contemporary piano pieces because they often use very unusual combinations and progressions of notes. Classical music, on the other hand is based on typical patterns - chords, arpeggios, progressions, scales, etc. A further goal is to learn to recognise patterns of patterns at a glance. This is God-mode of sight-reading.
This brings us to the importance of practicing your scales, arpeggios, and chords in all keys – once these can be played with very little effort, you will match them with what you see in your score, and as a result you'll be able to sight-read most music without having to read each individual note. The end goal is to be able to read patterns, not each note, in other words – read words and sentences, not letters.
To sum up:
- Condition yourself to keep a chosen tempo at all costs, and to look ahead.
- Practice your scales, arpeggios, and chords (in all voicings) in all keys.
- Read patterns, and patterns of patterns, not notes.
For what it's worth, I'm pretty sure it's not very easy to teach oneself to sightread. I use many, many strategies with students, very few of which would work with an individual who was a beginner, alone.
There are many aspects to learning how to sightread, and for me, the most important is - find a teacher!