As librarians, grad students, and professionals, you'll be asked to write memos, reports, press-releases, news, reviews, and so much more. That means you should practice your writing skills regularly. Hone your knowledge of sentence construction, spelling, and grammar. Learn to proof-read your own work and that of others.
If you take a tenure track, academic librarianship job, you'll be writing articles for journals, and even books, to get that desired tenure and promotion first to associate professor then full. Again, that means writing and more writing.
No matter the position, you'll need to be able to craft a memo, letter, review, and report so that it is readable and to the point. The written piece should be in the correct style; academic, formal, or informal, formulaic or free-form. Once you master the writing style of your current position or institutions, you'll move on and have to master a new style, a new set of guidelines and expectations.
Gregory Semenza writing for the Chronicle https://chroniclevitae.com/news/616-the-value-of-10-minutes-writing-advice-for-the-time-less-academic has some sage advice. Write for 10-15 minutes every day. In that short time, you'll get something started, honed, or even finished. In the short block of time, you can focus on your topic and stay focused.
Thomas Eakins, The Writing Master
I know when I sit down for a short writing session, it often morphs into a longer, very productive session where that task I've put off is accomplished. Ten minute increments are great for the short, quick items on your 'to-do' list. Instead of complaining you don't have the time, sit down and do it.
William Zinsser, the famous writing essayist who wrote "On Writing Well, 30th Anniversary Edition: The Classic Guide to Writing Nonfiction
" and "Writing To Learn
," recommends writing clearly and concisely, eliminating all the flowery flourishes and jargon.
If you don't like these books, I have lots of others with great writing advice, including A Beginning, a Muddle, and an End: The Right Way to Write Writing, a very cute story.
In the end, the best way to hone your writing skills is to write regularly. Try different styles, work your ideas out "on paper." If you cannot get the words to flow on paper or the computer screen, try a recorder. Talk to a friend about your ideas while recording yourself, transcribe your notes, then edit and polish.