Make a List
Camping requires a lot of stuff. You need clothes, toiletries, cooking gear, food and your tent -- it seems like a never-ending list. The hardest part about packing for your trip is remembering all the items you might need. The only way to make sure you get them all is to make a checklist.
Make your list on your computer and save it. That way you can print out a fresh list for every trip. Organize the list into related categories, like food and cooking, clothes, tent gear, first aid and medical, and entertainment. You might have separate sections of the list for different types of trips, or for different seasons. You won't need the swim trunks for the fall backpacking trip, and you won't need the tent stakes if you're camping in a trailer.
There are a lot of sample lists on camping websites that can get you started, but you'll definitely want to customize your list. Your entertainment section, for example, might include a baseball and a pair of baseball gloves or a pile of comic books. Some people enjoying cooking elaborate meals over a grill or camp fire, and need all the utensils to make it happen. Others get by on hot dogs and beer.
When it's time to pack, use the list as a guide as you gather everything together. Then, check each thing off the list when you actually pack it. That avoids the, "I set the pillows on the kitchen table, didn't you pack them?" problem. Then it's easy to scan down the list and see what you still need.