I am applying for Masters program in Computer Science and hoping to specialize in AI/ML. I will be the Teaching Assistant (T.A) for Machine Learning class in the spring and most of the admissions deadlines are in the end of December. I think having this experience can make my application strong but how can I add this experience to the application as it will be in the coming future?
The best way is probably to get one of you letter writers to mention it "K.S. will TA for my course in ML this coming term." Something simple. This shows you are both trusted and respected.
You can mention it in a simple way in a SoP or a CV.
Don't overdo it. If you make it sound like your biggest accomplishment you will probably not benefit.
The normal decision process is based on other things. Make sure you focus on those.