Take your time and project. Fully enunciate your words, and say your words with conviction. Take the time to think about what you are going to say, and remember to speak low and slow.
Confidence is key to keeping an even and articulate tone. Look up what a "stage whisper" is. It's basically when an actor needs to whisper on stage, but obviously can't whisper because no one would be able to hear them. Even when you are speaking "low", you can still project.
For some more info on confidence, give this a read...
http://askyourselfy.com/index.php/2016/ ... -strength/
I hope it helps.
Writer, entrepreneur, life coach, man's man, traveler, friend.