I'd be interested to know how I'd eliminate Caloptilia syrin*gella and Leuco*spilapteryx venu*stella. They all look pretty much the same to me.

Yes, they are all similar. On the forewing, Acrocercops astericola and L. venustella have the same pattern of black-and-white angled bands, and a whitish hind margin, on a ground color of uniform brown, whereas in C. syringella, the pattern is more diffuse and complex. As for differentiating L. venustella from A. astericola, perfect, newly-emerged (e.g., reared) individuals of L. venustella have the brown ground color of the forewing somewhat darker than in A. astericola. In flown specimens of L. venustella, however, the brown becomes worn, so that it appears paler than in a perfect individual. At that point, I don't believe it can be reliably differentiated from A. astericola on sight identification.