Putting Thoughts into Words?

I find it difficult to concisely convey my thoughts. I'll often listen to others speak, or read articles or quotes, and be impressed (and envious) of how they/it were/was able to clearly, fluently, and eloquently say what they needed to say; especially concerning matters or thoughts that, to me, seem difficult to articulate. Are there any ways to acquire this quality? Due to time constraint, I don't think speech cles are possible. I'd highly appreciate suggestions on how to work on this problem on my own time. Thanks!