When choosing a payment system, check how well it integrates with your e-commerce platform and whether it has ready-made plugins or APIs. Pay attention to transaction fees, settlement times, and the quality of customer support. If you plan to sell internationally, select a gateway with strong multi-currency support and consider adding Cryptocurrency Processing, as it can help reach customers who prefer digital assets. Also, make sure the checkout is fast, mobile-friendly, and tested for a smooth customer experience.