Effective pronunciation teaching always has these components
1. Raises awareness by helping students notice the difference when they hear it, and recognize when they produce it. For vowels and consonants, use tools like manythings.org/pp for listening recognition, and feedback loops like englishcentral.com for feedback about pronunciation
2. Shows visual demonstrations: http://www.uiowa.edu/~acadtech/phonetics/
3. Asks students to describe how they are currently making their sounds; it may be the first time they’ve ever thought about what’s going on inside their mouths when they speak
4. Teaches the movements needed for articulation of the sound: ex. of me explaining ER sound
5. Gives time for experimentation, and give enthusiastic feedback on successes.
6. Builds in regular, short practice times, to revisit what has been gained. New skills must be used to be maintained, otherwise speakers will slip back into unconscious, innate, first language habits.
Students must learn how the new sounds feel and sound, and build habits with concentrated practice. Long term mastery is developed by working hard to instill new habits of movement and voicing, and then regularly revisiting the new skill set.