Haha well it's easy then please send us the MIDI, Openscore, Lylipond, MP3... anything really, of a composition of yours that will be as appealing as Twinkle Twinkle Little Star.

What else do I see: congruence between melody and lyrics, harmonic depth, dominant half-cadence in the tonic arrival. Also the versions by Mozart add a lot and explain a lot of the endurance of the tune I guess. That has chromatic passing, secondary dominants, even a parallel minor (in the 8th variation)

If I may plug here the Berklee College online courses as a satisfied customer I can say if you are ready to put in the effort they are great.