Large infrastructure projects such as ports, electricity infrastructure, transportation infrastructure, water infrastructure, and digital infrastructure are seen as the backbone of the logistics infrastructure of a country or its long-run economic competitiveness. A significant change was noted in the market for project finance from 2020 to 2025. The period started with a phase of capital retrenchment following the pandemic, which was followed by a phase of high base rates, where the interest rate was regulated by the US Federal Reserve at a level of 5.25%-5.50%, which is the fastest increase in forty years. In addition, a reduction in balance sheets for banks, an increase in the speed of adoption of ESG factors, and an increase in awareness about climate-related factors were noted. A reduction in private participation in infrastructure (PPI) was noted from USD 96.8 billion in 2019 to USD 45.7 billion in 2020, which then increased to USD 86 billion in 2023. This was a volatile period for the market for project finance. The purpose of this paper is to outline a structured narrative review of the published research between 2020 and 2025 on debt structuring and investment strategies for large-scale infrastructure investments. The argument is that the key to capital efficiency in infrastructure finance is not "leverage," but rather the concurrent optimization of the three interdependent design elements of risk-aligned contract architecture, a capital structure that is aligned with cash flow quality, and structural control mechanisms. The combination of the three elements of a well-structured infrastructure finance solution is referred to as the Infrastructure Finance Efficiency Triangle (IFET). It is a new approach to making decisions based on the synthesis of the published research. The paper reviews the following eight categories of financial instruments along the three dimensions of risk position, return sources, and capital efficiency. The benchmarks are as follows: the yield on infrastructure debt is 4.9-5.1%, five-year default rate is 2.4% versus 9.6% for non-financial corporates; DSCR is 1.20x-1.50x; DSRA commitments are six months' debt service; debt equity ratio is 70/30 for contracted assets [12]. The paper provides a structured review of the following three case studies: a solar power purchase agreement, a toll road concession, a RAB-regulated water utility. A seven-step implementation roadmap is provided.