Both are great resources for explaining some of the more arcane parts of Tolkien’s universe that the films don’t go deep into. Read some context. If something is mentioned in the films that you want to know more about, there’s always Google! Alternatively, you can try the LOTR Wiki or Tolkien Gateway.
Howard Shore’s original score for the trilogy is sublime. That said, you also don’t want to take too long of a break and lose all momentum. You don’t want to dive immediately into the next film after finishing one, without taking a breath.
Give yourself a 15-minute break in between films. Walk around the house, do some light stretches or jumping jacks.I’d recommend eating breakfast or a light snack before you start, then preparing or ordering some food between the first and second, or second and third, movies.