I learned, for lack of a better term, a formula, for playing ballad stride.  I'd like to share it here.  

    The left hand is rootless chord based.  To review from a previous post, the LH can play in ascending order, 7-9-3-5.  Note:  For the purpose of this tip, we will use the interval of 2 and 9, as interchangeably.  From a pure theoretical definition, those intervals have a difference, but for here and now, we will consider them to be the same.

  Using a C chord as a model, 7-9-3-5 translates to B-D-E-G.  

    Now that you understand that, you will have to get comfortable with learning this structure for all twelve major and minor chords.  

 You don't have to play the 7-9-3-5 pattern all the time.  In fact, I recommend against using this formula exclusively.  You can also use 3-5-7-9.  Notice that the intervals here are the same, only the order has changed.  You will also see that in a C chord, E-G-B-D is also the spelling of an Em7 chord.  In other words, this voicing is the same as the third degree in the diatonic chord progression.  This will greatly help in memorizing this voicing.  

Again, please memorize this for all major and minor chords.  

  When you have this under your fingers, you can apply this knowledge in this fashion: 

On beat 1, play the root in the bass.  On beat 2, play the outside voices.  For the C chord, that would be B and G together.  On beat 3, play the inside voices.  That would be D and E together.  On beat 4, play the outside voices again.  

  The previous example is an illustration using the 7-9-3-5 voicing.  The pattern holds true for the 3-5-7-9 voicing, as well.  Unless requested by a member,  I am not going to spell out those pitches here.  Please try that on your own and if you have questions, please write back to me and I will spell out what you request.