I've never had any good luck with all those "store bought" tent stakes, so I make my own. They are always too flimsy or short to hold if you have any sort of wind or loose/sandy soil.
My normal tent stakes are around 12 to 14 inches long made out of 3/8 inch iron rod with a T end or eye loop on the end. For loose/sandy soil, or if bad weather is coming, I use 24 inch long stakes made out of 1/2 square iron with an eye loop on the end. I used wood stakes for years, but got tired of breaking and the replacing them. I made them out of elm branches 3/4 to 1 1/2 inch in diameter - from trimming all the trees. I would cut them off just below where a small branch split off, which I would nip off about an inch out. This gave me the Knot area for extra strength pounding it in, and that stub branch helped keep my tent loop or rope from slipping off of the stake. I would make them about 14 to 16 inches long, point the other end, and strip the bark from the bottom 3/4'ths of it - the portion that would be driven into the ground. They worked great, especially when I still had my tipi, but I had to continually replace them as they broke.
Sandy soil just means using longer and bigger stakes. But that "buried anchor" version also works great. It's amazing how well a 12 inch long branch/stick with a rope tied around its middle will hold when buried in the sand a foot or more deep.
The key thing is to angle your stakes into the ground/sand. And angle it in with the top sticking out away from the force of pull from your tent or tarp. It's easier to pull out a stake that is put straight down into the ground than one that is angled away from you.
Over at a friend's blacksmith shop along the Mississippi River, we make a Sand Anchor for people with boats to use when tying up along a sandbar in the river to fish/party/camp. We make them 5 feet long out of 1/2 inch square iron bar, with an eye loop on the end and a triangle extension welded on the side - to help you push it into the sand with your foot. You push them into the sand with the top part angling away from your boat and the water. They can be pulled back out pretty easily when you pull them straight out in line with the stake, but hold really firm when the force/pull is from the side away from the angle of entry.
I hope these simple ramblings help.
Mikey - out in the Hinterlands