Now that you know about the telephonic round,you should first
practise at home.
there are comman questions that are asked in any interview,like-
your introduction,why do u want to join the call center industry and so on.
It is very important to make a good impression on the listner in the first few mins.
you need to sound confident and the key to it is -BE YOURSELF.
dont get nervous,speak as if you are speaking with someone you know