Oooh, you’re a braaaave person… 
IMO the younger kids are easier, since the older they get, the more likely they are to ask the really awkward questions, like, “Why do people have to die?”
True story: The Better Half was teaching a group of 5th and 6th graders, and as it happened they were all boys, and in the course of the lesson, a “eunuch” was mentioned (don’t remember what the Bible story was). Anyway, so they wanted to know what a “eunuch” was, and so Mr. Goose told them.
And they didn’t believe him. “Nawww, nobody would ever do that to himself…” Mr. Goose had a reputation as a great kidder.
Anyway, one big piece of advice I would give you is to try to avoid the “video” trap. This is where you say, “I don’t have a lesson planned, so we’ll just watch a video.” If you start doing that, you will have turned your Sunday School class into an entertainment period, rather into anything educational, and ever afterwards you’ll be hearing hopeful requests from the kids to “just watch a video”. Dunno about you, but I have a problem with kids who come to church hoping to watch videos.
Ditto the “candy” trap, which is where you hand out candy for things like memorizing Bible verses. Once you start, you’ll have to keep doing it, and heaven help you on the Sunday you realize you’re out of candy. Also, the fact that a kid got candy from her Sunday School teacher but her siblings didn’t get candy from their teachers can cause unpleasant family friction in the car on the way home. If you want to reward them for memorizing Bible verses, use something like Oriental Trading trinkets, or stickers (big fancy ones, for this age group).
Something I like to do is keep cheap (well, inexpensive–you know what I mean) Bibles in my cabinet, because you’re going to have kids who don’t own a Bible (yes, there are people who come to church who don’t own Bibles), and it makes a big impression on Kiddo Without A Bible for her teacher to pull one out and say, “Here, this is for you–I think it’s important for everyone to have a Bible, so I keep extras around, just in case.” And make sure you inscribe it suitably, “To Kiddo, From Teacher”, so the parents, and the kid, know that it’s not just a loaner, it’s a gift. If the parents come up to you in embarrassment and try to give it back, just say, “Oh, I just enjoy having Kiddo in my class so much, I just wanted to give her a present…”
And make it a real Bible, with the Old and New Testaments. I don’t think much of those pocket New Testaments, since they’re only half the Bible, right? Christian bookstores have inexpensive editions called “student Bibles”, and if you buy more than one and tell them you’re a teacher, they’ll almost certainly give you a discount.