Off the top of my head, ‘Misty’ is one of the easiest tunes that i can think of where you can practice playing with feeling and actually hear you are playing with feeling, compared to a lot of standard tunes. it has a lot of simple expressive notes conveying a detached sound. i’ve listened to a few students of various ages play misty and theres no feeling in the way they play it, but again that comes with working on pitches (putting in the boring interval practices, its more a case of listening and working with pairs of notes like in intervals and hearing how they interact with each other, if you just practice a single note on its own with a tuner, you don’t get to hear how that individual pitch can sound so different when it’s played next to a different pitch – it actually helps you to hear the colour and depth of a pitch better.) Playing misty is great because some of those pairs of notes (intervals) can sound so different by playing them wrong dynamically (volume) or wrong in note duration (timing) by controlling both with the diapragm you can start colouring the pairs of sounds and develop better feeling to the listener.