Unfortunately, "Twinkle..." does not give much mnemonic aid.

The Greek alphabet was a reinterpretation of the Semitic alphabet, taken over from the Phoenicians. Nothing misty about that, since ancient Greeks were generous enough to pass on the story.

Semitic languages have quite different sounds (only consonants are written), nevertheless the order, shapes, and even some of the Semitic names were preserved more or less respectfully. Later some letters were added or "multiplied", others were omitted. Often pronunciation changed more quickly than spelling.