Well this nothing new for bushcrafters and woodsmen but I just thought I'd share one of mine and couple things I do and look for. The main benefit of this is that you don't have to carry stakes with you so it reduces your load. You can easily do this with your knife or hatchet/axe.
First off I find that seasoned woods work best as they are harder, my preference is seasoned cedar or oak but most any wood works. If all you have is greenwood you can fire harden both ends to make them more solid. You don't want a piece with a crack already forming as this will split with force when you hammer it in. You want to find a straight and round piece. I like them around 1" wide and around 10-14" long depending on use and conditions.
Once you have your piece of wood chosen it's pretty simple. You want to carve almost a spear point in the bottom end and make another cone/spear shaped end at the top, just don't make it as elongated as the bottom. This cone shape will prevent the wood from smashing and splitting apart. Once you get a split in the stake it doesn't hammer in nice. This helps reduce that significantly. Then about 2-3" from the top make your notch to hold your string/rope. Size of the notch really depends on how thick your rope is.
Here's a quick one made of oak
Now you don't really know for sure if you have a good one until you can hammer it in
Thanks for looking