I consistently give two pieces of advice on here: read and write. These are the same things I’ve been told would make me successful since I was a child. In addition to those two, speaking has played a major role in my early successes. But, if I give you a piece of advice that could make you a better writer, it would be to read more. Read anything that relates to your subject matter. Follow companies and publications on Twitter and Instagram that will help you become a better professional. And, after reading articles that they post/retweet, write a review on it. Even if you don’t post your review/reflection, the fact that you’re digesting the information will allow you to better articulate yourself when discussing the subject.
In addition to reading your subject matter, read the work of great writers. You need to learn how to write. And we can all continue to get better. I’ve been writing formally for over a decade and I still have grammatical questions. When those questions come up, I reach for one book: Elements of Style by Strunk & White. Very few people know all of the rules and this book isn’t fully inclusive but it’s pretty close.
So, I’ll leave you with this: Read more so you can write better and, therefore, you will be able to speak more confidently.
And, as a gift from me to you, here’s a PDF copy of the fourth edition of The Elements of Style. Go forth and prosper.