There are a number of very interesting essays in the collection titled Clarissa and Her Readers: New Essays for the Clarissa Project, ed. Carol Houlihan Flynn and Edward Copeland (New York: AMS, 1999), but two that stand out as especially useful for thinking about matters in today's reading are as follows:
Juliet McMaster, "Reading the Body in Clarissa" (189-212), on theories of acting and the expression of emotions in eighteenth-century psychology
Isobel Grundy, "Seduction Pursued by Other Means? The Rape in Clarissa" (256-67), on the intellectual, legal and literary contexts for Richardson's use of the term and concept of "rape"