The first day of English class is a great time to get students acclimated to the expectations of your classroom and get them excited for the type of work you will be doing with them. Focus on practical, creative work that gets students engaged, thinking and working with one another.
Students are likely to do group work throughout the year in English class, so make the first group project about introductions. This will also give you an opportunity to get to know your students. Pair students with someone they don't know and have them "interview" each other. Instruct students to learn their partner's name, a few hobbies and facts, and something relevant to your class, perhaps their favorite author or book. Give students 10 minutes to interview one another and then have the pairs come up to the front and introduce their partners to the class.
Before and After
Teens learn a great deal in a year of English class. But more than acquiring facts, they acquire new skills. Take the first day to write a brief assignment that's specific to your course. This may be a poem, a short story or a simple business letter, depending on grade level. Collect these papers and store them until the end of the year. Do not grade these papers--simply announce to your class that you will compare their first paper with their last paper at the end of the year to show them how far they've progressed in English as well as how much they've matured and grown as individuals.
Have each student write a brief paragraph about themselves. This should not be a simple biography, but rather an interesting anecdote about a favorite memory, a unique hobby or skill. Collect the papers and read them aloud. Have students in the class try to guess who wrote each paper, then have the student who wrote each paper make their presence known. This gives students a chance to meet each other, plus to learn a little bit about stereotypes. Students will make assumptions based on many hobbies and skills, but it might turn out that the kid who is good at basketball isn't the tall African-American boy, but the petite, quiet girl.