If you ask me, I like to reflect (and inspire my students to do the same) on learning languages and what works and what doesn’t, so I’m always happy to offer to my students such opportunities.
Here is a worksheet that brings actual learning languages experiences into class: some practical advice (from professionals!) how we should do it, and a lot of opportunities to discuss how your students do that. The worksheet is based on an article “How to learn a new language: 7 secrets from TED translators” from TED Blog. If you do all the worskheet’s tasks, it should take you around 90 minutes, and probably one of the last activities will be left as a homework.
You can start with some general talk about learning laguages (see p.1 for some quotes and ideas”, then proceed to the reading and matching, and then do the follow-up tasks focusing on the vocabuary. This lesson plan is suitable both for group and one-to-one setting.
I should also say it’s good to provoke a discussion about various ways of learning (and probably teaching) languages, as there has already been some time since I wrote and started using this worksheet with my students.
TeachingEnglishNotes 
Thanks for this. TED provides for excellent lesson material. Your post reminded me of this talk on language learning by Tim Doner https://m.youtube.com/watch?v=xNmf-G81Irs. I’ve used it a lot with higher level students, they love it.
Olga, thanks for the link! I didn’t know about that talk, and I’ll definitely use it with my students in future/