You're applying for an internship. You're writing a cover letter to send with your application. You list some of your best qualities.
“Before we get started, I wanted to remind everyone that your time sheets are due to Amy by the end of this week.”
You're in charge of a meeting at work. There's one announcement that you need to make at the beginning. You remind everyone about something that they're supposed to do.
You organized a professional conference. The conference has finished now, so you write a message on Twitter to thank the speakers and the people who came to the conference.
Your roommate had a really bad day and she's upset. You think that she should go to sleep, and she'll feel better tomorrow. You give her this advice.