My shooting position at Boomershoot. I was travelling fairly light, so I was basically limited to throwing down a tarp and two mats, with minimal sandbags. I was able to borrow sandbags from other people there and next time will definitely bring more (mind you, I might acquire the filling material locally). Others who were there put a lot more effort into preparing their spaces.
It's not immediately obvious but most of the actual targets are in the left of this picture, with the furthest out starting about the center line. The picture was taken before adjusting the shooting position to more closely match the target area. Note how the mats are set up perpendicular to the berm when they should be pointed substantially left.
At the top left of the picture you can see a patch of snow. That's about 500-600 yards away and provided a good range marker for the two days of the PRC. It was mostly gone before the actual event and the targets in the snowfield itself pretty much got rid of any remaining snow.
The device on the tripod is a spotting scope, sort of like a telescope but optimized for a wide field of view. It's easier to see a bullet impact through a spotting scope than a riflescope, though a good riflescope can definitely be used. My spotter and I traded off between the two. One definite advantage to the spotting scope is that you can get your head out from behind your rifle; after three days of shooting pretty much all day, I was definitely having trouble remaining in the right position to see and spot through my riflescope. It's one good reason to make sure your shooting position is as comfortable as possible -- at least if you'll be stuck there for three days.