How does one cultivate uplifted energy (paggaha)?
From your quote, it sounds like the lack of uplifted energy is the hindrance of sloth and torpor, one of the five hindrances to practice. To quote Ajahn Brahmavamso:


  Sloth and torpor refers to that heaviness of body and dullness of mind
  which drag one down into disabling inertia and thick depression. The
  Lord Buddha compared it to being imprisoned in a cramped, dark cell,
  unable to move freely in the bright sunshine outside. In meditation,
  it causes weak and intermittent mindfulness which can even lead to
  falling asleep in meditation without even realising it!
  
  Sloth and torpor is overcome by rousing energy. Energy is always available but few know how to turn on the switch, as it were.
  Setting a goal, a reasonable goal, is a wise and effective way to generate energy, as is deliberately developing interest in the task at
  hand. A young child has a natural interest, and consequent energy,
  because its world is so new. Thus, if one can learn to look at one's
  life, or one's meditation, with a 'beginner's mind' one can see
  ever new angles and fresh possibilities which keep one distant from
  sloth and torpor, alive and energetic. Similarly, one can develop
  delight in whatever one is doing by training one's perception to see
  the beautiful in the ordinary, thereby generating the interest
  which avoids the half-death that is sloth and torpor.
  
  The mind has two main functions, 'doing' and 'knowing'. The way of
  meditation is to calm the 'doing' to complete tranquillity while
  maintaining the 'knowing'. Sloth and torpor occur when one carelessly
  calms both the 'doing' and the 'knowing', unable to distinguish
  between them.
  
  Sloth and torpor is a common problem which can creep up and smother
  one slowly. A skilful meditator keeps a sharp look-out for the
  first signs of sloth and torpor and is thus able to spot its approach
  and take evasive action before it's too late. Like coming to a fork in
  a road, one can take that mental path leading away from sloth and
  torpor. Sloth and torpor is an unpleasant state of body and mind, too
  stiff to leap into the bliss of Jhana and too blinded to spot any
  insights. In short, it is a complete waste of precious time.