In my case I am self taught. I never really had to time for a music teacher, plus there were expenses to consider. I also like to learn at my own pace.
The main way I leaned was from examples and used minimum theory. Note that you will need at least some form of basic theory to proceed in any musical instrument.
How I taught myself piano
- Memorized major scales, start with a couple a week
- Learned how to construct major and minor simple chords (online tutorials etc)
- Memorized what chords are in each seven notes (I used a white board to refresh my memory – very important)
- Developed how to play melodies with the right hand (basically mirroring the left hand)
- Learned to play chords with both left and right hands
- Practice playing along to backing track on YouTube – invaluable !!!
- Learned 9th, Dominants and other extended altered chord – Google !!
- Experimented with chord progression
- Practice and more practice
There are of course books how to teach yourself piano. However you may end up being caught up in more theory than actual piano playing. The learning process never really ends. I am discovering more of more things every month. My most recent advance is playing in time to fast tempo e.g. over 150 bpm especially jazz. This used to be one of my weaker points.
I have started to upload some videos how to teach yourself piano (sample below). The video will be available both here and on SkillShare in the coming months.