Matches, flashlight, rain gear, can opener, dry socks, hat, bug repellent, easy food, coffee pot, coffee, rope, duct tape, first aide kit of some sort, compass, fork and spoon, fishing line and hook. common sense, whistle. water for drinking, 

Car camping or backcountry?

A quality sleeping bag, pad,and tent. Also bug repellant doesn’t hurt either.

I suggest that you download the packing list from the rei site. https://www.rei.com/learn/expert-advice/family-camping-checklist.html. I did cross off stuff we didn’t need and went from there.
 

A foldable saw to clear debris from trails (in addition to the other go e suggestions!

Firestarter — doesn’t have to be the chemical kind — but something that helps you get a fire going when the wood is wet.   I’ve used an old cotton towel which I have torn in strips and then dropped wax on it — it lights easily and burns hot to dry out the wood and you can fold it into the little sandwich bags.
Waterproof bag for your sleeping bag, especially if you’re hiking or canoeing.   They don’t dry out easily if they get wet.
Spend the money on a good inflatable sleeping pad — not getting a good night’s sleep makes even a good day miserable.    Ditto with good rain gear.

a decent quality tent with good fly coverage and quality screening
insulating sleeping pad not air matresses that inevitably leak
a hat with a peak such as a baseball hat with a rain poncho
fire starter, its just so much easier that struggling to light a fire.  Also have some idea how to build a fire
good meal planning

Hello Campers!
Depending on where you go, you might want a light folding camp saw, a light hatchet, & a light shovel.
And some Birch bark to start your fire.
Murf