My best advice for a new intern is — ask for criticism.
Sure, it’s nice to hear compliments and praise for how well you are doing, but that should balance out with some suggestions for how you can improve. Seeking out this criticism from a professional in your desired field is crucial to your success as an intern and in your future.
My suggestion is if you are writing an article, press release, blog post, etc. ask to see the edits made before they publish your piece and more importantly, ask why these changes were made. Not only are you seeing what you did wrong this one time, you can then apply this feedback to every piece of writing you do after that.
At my second internship, I was very up front with my supervisor and told him I wanted his feedback. After learning this, he sat down with me each time and went over grammatical errors I made or other suggestions he had to strengthen my articles. I learned something new every time we went over an article and my writing is stronger because of this.
Don’t assume your supervisor will give you the feedback you need. Ask for it. You’ll appreciate it.