I agree with the first two but on the third I would suggest that if you have a good idea of where they're going and your goal is to kill them to move to put them to your left around some cover. This should generally force them to left shoulder to pie slice more effectively which is generally going to reduce a persons effectiveness. There's definitely scenarios where this isn't advised such as the cover of the position that would put them to your right being more favorable if you feel comfortable shouldering left. Also, if a person is sprinting taking a couple of shots while they're out of cover is really good but I wouldn't spend the entire amount of that time firing at them. They'll most likely be looking at where they're running more than anywhere so if you cement the idea that you're somewhere by shooting at them but then move while they're still positioning and manage to be out of sight once they check again they'll act on faulty information while yours will be more accurate.