Well, perhaps I can help you. I am not doing or haven’t done a CELTA. However, I am student-teacher like you and I might be able to give you some advice. I am currently doing a Bachelor’s degree in ESL. What I can say is that always keep in mind that it is your career you are working on, so don’t be hesitant to asking questions and experiencing new things. Also, when you will be out doing a practicum, ask for opportunities and explanations. Listen to your students; try to find out what are their needs. Connect with them and get to know them so your activities will correspond to their interests. Don’t try to change the world, keep it simple while taking into consideration their learning pace and level.
Have a great one