Placing Traditional Passive Protection
When rock climbing and placing straight-forward passive protection, such as DMM Wallnuts or Wild Country Rocks (which we often refer to collectively as ‘wires’), remember that each piece of gear can be placed in 4 different ways (although 2 of them are rarely likely to seem different, so you can think of it as 3 ways.
First, try and place the piece with the curves in contact with the rock, facing left or right depending on what looks most promising. If you are not satisfied with this, perhaps because of some undulation in the rock that was not immediately apparent, then remove it and try it facing the other way (left or right). Finally, you could try and place it with the straight edges in contact with the rock.
Generally speaking, the more metal to rock contact there is, then the more secure the placement will be.