Well mate, not to make you start doubting yourself, but legs are about the last to show effects from cardio, diets, workouts.
Growing real muscle can make them look better as they take on the classic muscle shapes of bodybuilders legs, even with a bit of fat. That said, you would need to start doing squats, deadlifts and be pretty mean with yourself (go hard at it) to get the kind of look that would work.
You might start with finding out your body fat ratio to the amount of muscle, this may alter your direction to more diet control + some cardio.
Most peoples diets flap in the wind, as they never really got down to even a few weeks calorie counting, nor any adjustments to the diet from what is calculated. You say you have a 31 size waist, that sounds nice & slim, so it may be you need to study up on the food you eat as far as macronutrients is concerned (carbs, proteins & fats). Adjusting the amount of each is called fine tuning and this may be where you are at.
So give us some further feedback on your current bodyfat? to start with. DA