One of the things to remember is, as you change position from the prone to sitting, kneeling to standing, your Natural Point of Aim becomes a bigger factor. It’s at this point you see the largest effect of a poor natural point of aim. So given that time & opportunity, be sure to test your natural point of aim.
Close your eyes, go through a couple of breathing cycles and see where the reticle is. We want the vertical line of the reticle to intersect the target. Your elevation maybe slightly compromised do to breathing, but we want to be sure our left and right is correct. If you find you have excessive movement in the reticle, which can happen based on the quality of your support, at least try to get the movement centered so it goes the same distance to both the left and right of the target. This is often represented by a figure 8 or infinity symbol. We want to strive to get the center of the figure 8 in the center of the target.
The quality of the support is very much a factor, so be sure to practice where you and how you support by the rifle. This means not overextending yourself by trying to get the support too far towards the barrel. Yes the closer the support is to the end of the barrel, the less movement will be transferred to the shot, however there is a point of diminishing returns. It’s better to stabilize the shot so you minimize the movement. If the opportunity presents it’s self, maximize the contact between you and the support. A great example is the hood of a car, laying across the hood is better than hanging off it at the rear of the rifle. In word, Choke Up and across the platform as much as possible.
Do not blade yourself to the target. Approach your standing supported position square, point your toes at the target and keep the shoulders straight across as square as possible to manage the recoil. Picture a tripod when setting up the position. The support & firing hand create that the triangle withe body and the hands forming the 3 legs of the tripod.
The biggest benefits to a supported standing positions is,
Speed moving in and out of position
Seeing over an obstacle.