Many learning barriers are common and can be anticipated in advance.
When I start planning a lesson plan through UDL, I begin to predict the high-probability barriers that my students will face within the lesson. For example, I think about the challenges my students face in a seemingly simple reading assignment. Many of my students struggle with understanding basic vocabulary terms, which makes it difficult to read a text. The physical text could pose problems because students with visual difficulties or mobility issues could have difficulty reading from a handout. When I understand the high-probability barriers that exist, I can design engaging ways to represent content differently and provide students with options for demonstrating knowledge.
Provide links to further resources on the technique.