Here's a continuously updated list of the camping hacks the kiddo and I have tried or are interested in trying.
Cotton ball fire starters.
How to make it: Saturate cotton balls with petroleum jelly and dip in paraffin.
These things were incredibly useful for lighting our Emberlit backpacking stove in a drizzle. I made about 20 of them, and used a couple a day for the week of our last trip. The paraffin isn't necessary, but it adds some fuel and prevents your hands from becoming a sticky, oily mess when you get one out of the bag.
How to improve it: Don't use too much paraffin. I dipped mine twice, and it was probably overkill. I might experiment with wrapping them around a candle wick before dipping them next time.
Match fire starters
How to make it: wrap a strip of paper towel around a strike anywhere match and dip in paraffin.
I didn't use these as frequently as the cotton ball fire starters, but these were useful as well. Once the flame hits the paraffin-impregnated paper towel the flame grows significantly and burns for around five minutes.
How to improve it: I recently saw a variation using four strike-anywhere matches wrapped with cotton gauze. Don't put the paper towel too far away from the match head, or you'll have to wait longer for the flame to catch.
Frozen water bottles instead of bagged ice
How to make it: Freeze a dozen or more bottles of water before packing your cooler.
This really seems like common sense. Blocks of ice will last much longer, and when the ice melts, you'll have cold, clean water to drink instead of a soggy mess.
How to make it: Tear off a big sheet of heavy duty aluminum foil and pile meat, veggies, and seasonings in the middle. Fold to seal at the top and sides. Place on embers for 30-60 minutes, turning every 15 minutes or so. Eat right out of the packet.
This is a great way to make a good dinner without worrying about washing dishes. We've made pork, chicken, beef, and seafood this way. A few days ago, I did a Hobo Low-Country Boil for my mom's birthday dinner. I could probably do a blog post, or even an entire blog, about cooking this way.
How to improve it: Prep at home and freeze before placing in a ziploc bag. The steak will last several days.