In response to the question “where do I start to get into Bach?”, I gave this answer:
Start with simpler pieces, like 2-part inventions, the gorgeous Air on G String, the driving Cantata 29 Sinfonia, the serene Largo middle movement from BWV 1056 keyboard concerto. At this point you might think Bach sounds gorgeous and writes some fine tunes on par with Mozart.
You are now ready for phase two, the beginning of the real journey. I now suggest listening to one of the Schubler Chorales, eg BWV 645 or BWV 650, about 10 times in a row, perhaps several days in a row. This is your gateway. Notice how the piece starts with a pleasant melody, and is humming along when at some point this slow-moving hymnal tune intrudes in the background. Notice the relationship of that slow hymn (called the cantus firmus) to the rest of the piece: they’re almost totally unrelated! Yet somehow they weirdly fit together.
This strange relationship will puzzle and haunt you, and eventually open the door for you to appreciate Bach at a whole different level, and this is the level where Bach has no peers. At this point you can now start hearing his pieces in a new way. A good next step here is his Organ Trio Sontatas. These pieces each have 3 voices: bass, left hand, and right hand. Focus on following a single melodic voice with each hearing, then eventually on hearing them all together. Notice their independence, yet perfect interlocking fit. And don’t be afraid to crank up the volume, really feel it!
Finally you can tackle masterpieces like the mind-blowing organ preludes and fugues (eg BWV 578 fugue, BWV 548 prelude, BWV 552 prelude, BWV 678), keyboard works like Chromatic Fantasy and Fugue (and the obligatory Well Tempered Clavier and Goldberg Variations), and ultimately, his crown jewel, the Cantatas. Try BWV 106 for example, there really is nothing else ever written in its league, except for nearly all his other nearly 200 surviving sacred cantatas (his secular ones seem less inspired to me), and the passions (St Matthew and St John).
Stagger through the rest of your life in utter disbelief and wonderment. Search for live performances, and revel in the timeless insurmountable mountain that is Bach.