OK, here's some good suggestions:
1) Stand up when you talk. Most people get too relaxed when they sit and talk on the phone - and your voice may not project as well.
2) Print out a copy of your resume - so you can keep your past work histories straight as you talk about recent experience.
3) Make a list of 3 "success stories" -- where you saved a previous company time and/or money. Be prepared to talk about these events.
Best of luck !!