As for hitting spots where you want to begin shooting, I always look for something distinctive where I want to stop or measure off a fixed object like the end of a wall or a tree. I look for odd rocks. Clusters of brass/hills, a stick on the ground etc. it’s poor sportsmanship to place something to mark your spot and I have seen pint sized TRex looking pros do it in USPSA, but it’s not legal. You can almost always see something already there to mark your spot. When I am moving I then look for that sign and start slowing down as I approach it.