For a gourmet touch, consider using organic spinach, grass-fed ricotta, or gluten-free jumbo shells. Budget-friendly swaps include store-brand cheeses or a family-sized jar of sauce. If using fresh spinach (blanch and chop), ensure cheeses are good quality. If filling seems too wet, ensure spinach is squeezed very dry; a little extra Parmesan can help firm it up. Cook pasta just al dente to prevent shells from breaking; handle gently when stuffing. Always ensure good sauce coverage on bottom and top to keep shells moist. For richer flavor, brown ground beef or Italian sausage and mix into the marinara. For a healthier twist, add extra spinach to the filling or use whole wheat shells. The dish is done when shells are tender, sauce is bubbling, and cheese is melted and lightly browned.