Saying or singing the words out loud will make it easier to remember. You are reinforcing the visual image of the words with the sound and with the physical position of your lips and tongue. Associate words with images or symbols, the more vivid the better. Make the image imaginative, humorous, exaggerated. Use color and movement to make it more vivid.
Sexual images are particularly easy to remember.
Associate a foreign word with a word you already know. For instance, the French words tu fu could be associated with tofu picture a bowl of tofu with chopsticks. This will take some extra work when you first start learning a song, as you must choose images for each of the words, but it will save you time in the long run. You may even try a journey technique, where you associate each word of a song with an image, then combine the images into an imaginary journey. We will have pronunciation practice tapes for the French and Breton songs with a language expert speaking the words.