In industry and labs, predictive models describing processing-structure relationships are inherently valuable, yet few exist for cation ordering in perovskites. In this work, 15 compositions in the [(NayLi1-y)((1-3x)/2)La(1+x)/2]TiO3 (NLLT) system (y = 0.25, 0.5, and 0.75; x = 0, 0.0533, 0.1, 0.1733, and 0.225) were synthesized using a conventional solid-state mixed-oxide method. X-ray diffraction data show that some degree of long-range ordering of A-site cations exists for x >= 0.1, although electron-diffraction data indicate that short-range ordering exists even for x < 0.1, with the degree of ordering decreasing as the value of x increases. Empirical models have been derived for the A-site ordering parameter (eta) as well as the resultant expansion (Delta r(A)) for each y series in the NLLT system, from which two general models were derived for perovskites with any arbitrary degree of 1:1 layered A-site ordering. These general models allow for the prediction of the order parameter and resulting expansion using only published ionic radii data.