As a first-year teacher, how do I keep my focus on the MOST IMPORTANT things this year to create a positive experience for my students? What are those most important things?

I want to make sure my students have a positive, welcoming, and empowering experience in my classroom. I am wondering what essential things I need to focus on to make sure this happens, rather than getting distracted by things that seem urgent but are actually less important- because there are SO many things! (: