As you probably know, kids are always ready for adventure. These days much of the adventure happens on a TV or computer screen, so they may not be as enthusiastic as you would want them to be when you invite them on a family camping trip. Once they go, however, they will totally change their minds.
Showing excitement yourself about the trip will go a long way in getting the kids excited. Show them pictures of the campground so that they can start forming an idea in their mind of the place they will be visiting. Let them help with the planning and be sure to allow younger kids to bring a favorite toy so they will not feel alone.
Remember that your need for a shelter will be very different from when you were still single and hiking solo. That was when you could get away with just taking a portable hammock or one man tent. Younger kids will feel more comfortable when they can sleep with their parents in the same tent, so make sure that the tent is big enough for everyone to be comfortable. A family of four may find the space that a four man tent offers, a little tight and may prefer to use a six person tent or an even bigger tent to be able to store clothes and other essentials inside the tent.
Having a camping checklist is essential. A great list can be found at Love the Outdoors, http://www.lovetheoutdoors.com/camping/checklists.htm. You can use it as an example and customize it to fit your family's needs.
Arriving at your campsite while it is still light, will help your kids to become familiar with their surroundings and will be less scary for them than a nighttime arrival. Every kid should have their own bag so that they will know where to find their stuff and they will learn to be responsible to return their belongings to their bag.
Every campsite has rules and it is important that you familiarize your kids with these rules as soon as possible after arrival. You do not want your kid to start breaking branches off trees thinking they are helping to gather firewood, just to find out that they are doing something that is forbidden. Kids need to learn never to feed wild animals and why that is important. Also check ahead of time if the park you will be camping at allows campfires. It can be very disappointing, even for adults, to find out that they will not be able to make their beloved s'mores.
You do not have to pack a lot of toys since there will be plenty of distractions to keep the kids busy. Younger kids can be entertained watching squirrels or chipmunks, gathering leaves or forming words by arranging small sticks. Mom and Dad can also point out bugs or other wildlife and your kids will be learning without even knowing it. At night you can teach them about the stars and if you don't know much about the stars, bring a book and you can learn together.
Older kids may want to have their own tent and you can use a one man tent for them or they may even want to try sleeping in a bivy sack or portable hammock. Older kids may like camping more if they can bring a friend and you can get them a 2 person backpacking tent to see if they would like that.
Older kids can also help with pitching tents. Even bigger tents these days are made in a way that makes setting up camp easy.
Now all you need to do is make sure you relax and have a wonderful time with you family in the outdoors!