To ensure tender and juicy beef, select a tender cut like sirloin or flank steak. Slice the beef thinly against the grain to maximize tenderness. Marinate the beef in a mixture of soy sauce, ginger, garlic, and a touch of sugar. This marinade will infuse the beef with savory flavors and help tenderize it. For best results, allow the beef to marinate for at least 30 minutes before cooking.