I'm linking up with Fabulously First for a linky party.
My first year of teaching was brutal, not gonna lie! In fact I look back at that year and I am amazed I am still teaching, it was that bad! 9 years later I have learned a LOT mostly through trial and error (lots of error) but through it all I have always loved what I do! So I guess my first word of wisdom is love it!
That being said in my opinion the MOST important thing for a first year teacher
ESTABLISH ROUTINES AND PROCEDURES
Without clear and established routines and procedures your classroom will be chaos, and it is hard to teach in chaos and even more difficult to learn. I remember back in my college days reading The First Days of School, my professors driving home the importance of classroom management and yet for me it wasn't until I was in the trenches that first year that I realized just how challenging teaching can really be. Be consistent and clear. When your students know how to behave, what is expected, and that you love them you can teach. You can do amazing things. Take the time in the beginning to train your centers, lining up, going to the restroom, playing on the playground, sitting in an assembly, etc. Revisit the expectations when they need a reminder and always stay consistent.
Also... this one took me a couple of years to figure out but one thing I have learned DON'T TALK OVER THEM. If they are noisy and you need to speak wait for it to be quiet. If you start giving instructions while they are still speaking and not being attentive they will learn (very quickly) that listening to your instructions is optional, you will also find yourself repeating your instructions over and over.
Hope that helps, now I am going to go read everyone else's advice. You are never too experienced to learn from other teachers (just some more advice haha).