I am no expert, but a few things that helped me: 1. Read lots. 2. 30 Days to a More Powerful Vocabulary by Norman Lewis. Some the words I have inly encountere

I am no expert, but a few things that helped me: 1. Read lots. 2. 30 Days to a More Powerful Vocabulary by Norman Lewis. Some the words I have inly encountered once or twice in the intervening 25 years since I read it, but many others I hear every day. 3. The Elements of Style by Strunk and White. It’s like any other instruction manual. It’s worth reading, even if you don’t follow them.