Heart failure (HF) is a complex clinical syndrome with symptoms and signs due to cardiac dysfunction, leading to high hospitalization and morbidity. HF treatment has rapidly developed in recent decades, and breakthroughs have been made. Although conventional neurohormonal blockade therapies, including \beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), and mineralocorticoid receptor antagonists (MRAs), significantly improve the prognosis of patients with heart failure with reduced ejection fraction (HFrEF), mortality and rehospitalization remain high. Therefore, new therapies are needed. Previous studies demonstrated that ivabradine, angiotensin receptor-neprilysin inhibitor (ARNI), sodium-glucose cotransporter 2 (SGLT2) inhibitor, vericiguat, and omecamtiv mecarbil (OM) are beneficial for HFrEF. However, there is a lack of systematic review of the most optimal manner to use under various clinical conditions. This review summarizes the current knowledge regarding these therapies to give suggestions regarding clinical use timing, application scope, and optimal therapies under various conditions. Most importantly, we propose the HF diamond approach to express the necessity of conjunction of therapies. Different from the current guidelines, we suggest to use the diamond approach in an early and comprehensive manner at the beginning of ventricular remodeling in HFrEF to prevent further deterioration of HF and maximize the prognosis of patients.