Density functional theory is a workhorse of present electronic structure calculations. These are increasingly more applied in materials science as they allow for insight beyond experimental capabilities, testing hypotheses, or isolating various phenomena. Herein, an overview of the applications of the electronic structure calculations applied to extracting alloying trends, which, in turn, leads to refining of alloys, is presented. The topic covers the construction of structural models by properly considering site preference. Next are discussed alloying trends in structural and mechanical properties. The final part deals with microstructure features such as extended defects or multiphase constitutions. The unifying themes of the presented application are compositional trends in properties of lightweight intermetallic γ-TiAl-based alloys.