Hi, the method Pierre mentioned it's good and effective, and it's science based so it's good to give it a try. Combine it with flashcards, you can use just regular paper and pencil to create them or you can use app designed to this task. As you have plenty of time during commuting, I recommend to you to create every flashcard by yourself. The process of creating your flashcard helps you to remember the world. It's also good to experiment with different types of flashcards, rather than using just a translation of the word or phrase you want to remember, use a synonyms, pictures or definition written in the language you're learning. It's also good to create a personal connection with the word. It's easier to forget that cat is a cat, but if you connect the word "cat" with your sweet and little ball of fur named "Mr. Cuddles" it should be easier for you to remember that word.