The first suggestion I would make on the night time football is to ease wayyyyyy back on the noise reduction. In the digital age, there's this newly developed aversion to noise,and your first few shots show a high level of detail-killing noise reduction. It would be preferrable to show sharper images with a small to moderate amount of noise than the painterly, smeared effect that high levels of broad noise reduction causes.
On baseball, I would concentrate on getting into a better position, where faces are visible, such as shooting down at the 3rd base line or the visitors' dugout area, so you'll get better views of the players on the diamond. With a heavy lens like the 120-300, a monopod is a huge help for baseball, since it allows you to keep the camera trained on the area where the next play will develop.
Luckily baseball is a daytime sport, so that makes it easier to get good shots than night football under typically dim high school lights.