Speak slowly. If you are recording it via Skype, have post-its on your screen reminding your to BREATHE. You can also try to speak with your eyes closed. Don't worry about anything around you, only think about the flow of your speech. Don't try to speak faster if you think you are speaking slowly. If you are a slow speaker, people can understand you. If you talk like a race car, people won't know what you are talking about and you may stutter. And if you do stutter, STOP AND BREATHE. Don't try to finish the sentence. Never try to just get it out and speak that sentence as fast as possible. Take your time. You are valued by what you say, not necessarily by how you say it.