1) Know your venue.
Summer concerts are held in all sorts of places. Parks, pavilions, museums, here in San Diego, we even have them on the deck of an aircraft carrier! We plan our arrival time based on what else there is to do. Something like a museum, we arrive early enough to set up a blanket and let the kids run around playing. Other venues, like a closed off lot with a stage, we arrive closer to the start of the concert.
2) What to bring?
A lot of people bring lawn chairs to concerts. We do this for movies in the park, but during the concerts the kids spend more time on their feet than sitting, and often we're away from our spots, so it's easier for us to just bring a large, waterproof blanket. Machine washable is a must, because it inevitably gets something on it. I bring a separate bag filled with dinner and snacks, and that's really it.
3) What's to eat?
We've been to concerts where nothing is available to eat, where food trucks are present, or recently a concert that was catered by a restaurant with a small menu of premade food to purchase. But if you have kids, you know you're better off bringing your own, just in case. Our "just in case" always involves cheese and crackers. Right now Thatkid is a huge fan of "goat cheese sandwiches" or goat cheese between two crackers. Thatbaby is all about the gouda.
One of my favorite things to bring is sandwiches, and I love love love a couple of local grocery stores that have prepacked "kids meals" which come with a sandwich, drink, and snack (or two or three).
And of course, there must always be fruit. Which Thatbaby somehow always seems to take possession of.
4) What to expect. I've noticed a lot of parents try to get their kids to eat before the concert. Which is definitely one option. My kids need a little warming up to the music, so we start eating when the concert starts. This gives them time to watch and take it all in while eating.
Often by the time they're finished, they're ready to go up and join in the fun. Thatkid will take breaks from eating to run up and sing and dance to a song he knows. Thatbaby waits until he's all done, then wants one of us to go up close to the stage with him. Which is why we don't bring chairs.
The great thing about summer concerts for kids is that they're really geared toward them. There's usually at least one song that every kid knows, like Old MacDonald. And just as you love it when a song you know and love comes on the radio, kids get really excited when a band or singer is singing a song THEY KNOW.
5) The aftermath. In our neck of the wood, these concerts begin and end fairly early. Which means they extend the bedtimes of my children, but not by too much. And what really helps is bringing pajamas with us. We change the kids before heading home, so that when we get home, they can march right to bed. With a song in their heart.