help with phone interview

I need help on how to prepare for phone interview. From my past experience, I couldn't get the on-site interview if I had phone interview first, no matter who conducted the phone screen interview-HR or hiring manager, but if the phone interviewer skipped question and invited me for on-site directly, I normally can do good and get the offer. Now, I need to prepare for the phone interview, could anyone share your experience with me and how to prepare it? Thanks a million.