Read the business section of newspapers like the New York Times, the Washington Post, the Daily Telegraph, etc. and make a note of words that come up and their context. You could try putting phrases in to Google as 'quotes' and see what comes up. It might give you an idea of how they are used.

I think that would depend on what you business is. For me that would entail learning a bunch of computer related technical vocabulary. In general terms, I think you could ask ChatGPT to give you wordlists commonly used in your domain, for example. If there are any texts/books that you normally read in your native language related to your work, you could try reading them in English as well.

Listen to podcasts, read books and watch videos related to that topic. But, most importantly get conversational practice lessons, speaking is one is the most important aspect of learning a new language.