This chapter describes two principles for supporting trainees. The Scaffolding Principle describes how support should be adapted to accommodate a trainee’s current skill to keep them in a “high challenge/high support” learning mode. The Reflection Principle describes ways in which training should encourage active reflection in trainees so they can learn how to constantly reflect on their own performance and apply new insights to future situations. The chapter provides examples of intelligent tutoring systems that employ adaptive scaffolding techniques, along with other types of learning applications. The chapter also discusses strategies for encouraging learners to reflect on their training experiences.