How To Become Well Spoken?

I'm setting a goal to become better at articulating my thoughts and communicating more effectively. I watch a lot of media news outlets: Such as CNN to name in particular and the anchors and guest that are selected to speak carry there selves so well and speak clearly. I myself tend to use um and err a little and I'm looking forward to working hard to change those things. I ask that you be specific instead of just saying reading this or that could you please provide as much depth as you can answer my question thanks in advance.