Colonoscopy is essential for colorectal cancer (CRC) screening, but its effectiveness depends on adequate bowel preparation (BP), which remains suboptimal in up to 44 % of cases. Poor BP reduces lesion detection, particularly in the proximal colon, and increases procedure time, repeat exams, and healthcare costs. This narrative review summarizes evidence-based strategies to improve BP, highlighting high- and low-volume polyethylene glycol (PEG) regimens, including newer very-low-volume options with better patient tolerance. Adjunctive agents like simethicone and 5-HT4 agonists benefit select groups, especially those with constipation. Split-dose and same-day regimens, particularly with a <5-h interval before the procedure, enhance cleansing and adenoma detection. A 1-day low-fiber diet is now preferred for better compliance. Risk factors for poor BP include age, comorbidities, and socioeconomic barriers. Emerging tools, such as predictive models and AI-enabled apps, support personalized care. A patient-centered, risk-adapted approach is vital to optimize colonoscopy quality and reduce CRC incidence.