It means encouraging learners to take responsibility for learning and helping them to develop learning strategies and study skills. Most importantly, it asks learners to reflect on how they are learning. The aim of learner training is to produce effective, independent language learners.
Example
Learners think about what time of day they are most productive and then produce a diagram showing their peaks and troughs. Together they discuss how to plan study with this in mind.
In the classroom
Areas often discussed include ways of recording new vocabulary, different learning styles and preferences, finding opportunities to use English outside the class, reflecting on strengths and weaknesses, and study skills.
Further links:
https://www.teachingenglish.org.uk/article/snack-facts-recording-vocabulary
https://www.teachingenglish.org.uk/article/learning-styles-discussion-forum
https://www.teachingenglish.org.uk/article/unit-4-reading-skills