I agree never blurt anything out especially in a live environment. When i first started in radio I sometimes had trouble holding thoughts and expressing them I learned to write everything down like a script and follow it it saves a lot of ums and ahs. Avoid crutch words and phrases like at this time, Ladies and Gentleman or right now. It's OK to say once don't repeat it the next time at the same event.
If you want to record yourself and send me the MP3 let me know I'll be glad to "air check" you