Always carry a notebook.
Start a new page for each day shooting. At the top of the page write the date, and some sort of quick title. So when you flick back through you can find what you're looking for.
Under that write any instructions you'll need, like who you're meeting when you arrive or where you're going. You might require special equipment like a hard hat or steeltoes, so write it here. Perhaps you need a different lens because you're going to be in cramped locations. This is about thinking ahead.
Write down your goals of the shoot, what things are you hoping to photograph. Get thinking about any scenes you might expect, and how you want to capture them. Don't go wild though because it never ends up how you planned.
Keep the notebook within easy reach, like in your back pocket. Make sure it is easy to open to the correct page, with a pen ready. Write down anything you might find useful in the future. Names, what's going on, or things you want to arrange next. Grab peoples email addresses if they express an interest in your work. So you can email them some photographs later.
After a days shoot, sit down and have a look over your notebook.. Make some post-game notes, what could you have done better, what should you do next time, was there anything you forgot to write down?
Remember: Always carry a notebook.... and a pen.
P.s. I don't suggest using a phone for note taking as it looks rude to those around you. It looks like you're not focusing on why you're there, and are instead checking football results.