Using good quality bacon grease adds significant depth of flavor, but butter works well for a milder taste. Don't overcrowd the skillet; cook in batches if necessary. The cracked lid is key for slow simmering while allowing some steam to escape, concentrating flavors. Cook time for the beans is flexible based on desired tenderness – cook longer for softer beans, less for a crisper texture. Allowing the liquid to fully evaporate at the end helps caramelize the onions and peppers, adding sweetness and complexity.