Generative artificial intelligence (AI) is reshaping architectural practice, yet the literature offers little guidance on which practices matter most when the objective is not design production alone but the marketing of real-estate investment opportunities in a culturally distinct region. This study develops and empirically weights a best-practice framework for leveraging generative AI in architectural design to promote investment opportunities, using the Aseer Region of south-western Saudi Arabia as its application context. A structured review of the recent literature was synthesised into a hierarchy of five dimensions and seventeen practices, which was then weighted through the Analytic Hierarchy Process (AHP). Fifteen domain experts—architects, real-estate developers and academics—completed thirty-one pairwise comparisons each; judgements were aggregated by the geometric mean and the aggregated matrices proved highly consistent (consistency ratio = 0.024 at the dimension level). Contrary to a technology-first expectation, experts ranked governance, ethics and trust highest (26.7%), followed by local-identity localisation (21.0%), ahead of generative technology itself (15.5%). A sensitivity analysis excluding the least-consistent respondents confirmed the stability of this ordering (Spearman's ρ = 0.93–0.99). The findings are illustrated through a set of AI-generated visualisations produced for an Aseer investment site, and translated into actionable guidance for practitioners and decision-makers pursuing Vision 2030-aligned development