I've been parenting for five years now and for all that time I've been the sole grocery shopper.
I've gone with a single baby in the carseat, leaving no room for groceries, I've taken a toddler and a newborn in a baby wrap, and I've gone with three little ones.
You'd think by now that I'd have some idea what I was doing.
And yet, I keep making complete rookie mistakes that end in tears (mainly mine). Learn from my mistakes and don't ever do the following. Don't:
Introduce your children to the kid-size carts. Because when there aren't any, your child will lose their minds with sorrow, and when they do have them, you'll get your ankles smashed at least a dozen times. You lose either way.
Try to do more than one store in one morning. Every time, I think it'll be fine. Every time, it is not. Pick one store and be done. Saving ten cents on a gallon of milk is not worth hitting two stores.
Go at peak times. One perk of being a stay-at-home mom is that you can go when the grocery stores are relatively quiet, instead of after work or on the weekends.
Open a bag of snacks for your child. Once you cross that line, there is no going back. Enjoy having all your grocery bags full of crumbs and spilled treats when you get home.
Use those terrible race-car carts. Unless you enjoy trying to maneuver a bus down the cereal aisle. Because if you let your child do it once, they will want that cart forever after and you'll never again get to use a regular cart.
Try to pick the shortest line. Inevitably, you'll pick the one behind someone who wants to pay for their groceries in pennies (or a check!), or there is some item that needs to be price checked. Just pick the line closest to you and trust that you'll get through eventually.
Go right before lunch or dinner. You're just asking for a mega meltdown (as I discovered today when I was that mom with three children, two of them sobbing, in the produce section). Experts say adults shouldn't shop hungry because you'll make poor food choices, but I'd say you'll make even worse choices if you're shopping with a hungry toddler who wants every item on the shelf.
Let your toddler walk. My older daughter wanted to walk along side the cart at about a year. I didn't think anything of it but after that, she was totally done riding in the child seat. I learned my lesson and didn't let my second daughter walk on her own until she was close to two.
Make more than one trip in a week. Although I buy more groceries now because I have more mouths to feed, I also basically never make extra trips to the grocery store because there's no such thing as a quick stop in for milk. I have to be REALLY desperate for something to drag all three children in and out of the car for an extra item.
Also, I don't know why it is, but it seems that people handing out unsolicited advice seem to congregate at grocery stores. You're almost guaranteed to get a little nugget of wisdom like, "Shouldn't that baby be wearing socks?"