I would pretty much agree with what has been said so far. Reading your Master/Mistress like a book is one of the best ways to 'go the extra mile'. Maybe having something special ready for them, cooking them a special meal you know is their favorite, and/or having yourself availible at His/Her whim. To me those things are some of the key points of my own submission, though each submissive and each Master/Mistress will make their own niche and demands respectively.