Hi and welcome to the forum:
What lens or lenses do you have right now?
I would suggest viewing the following video:
Now, this is working at a level well above that under which I expect you will be functioning, so the gear they use is very expensive, but the focal lengths are interesting, and be aware that having cheaper lenses will mean lenses that don't function as well in lower light. For your camera to get the same Field of View (FoV), divide the focal lengths mentioned by 1.6. So it they say 70-200, you will get the same results as far as coverage with something like a 40-125mm.
If you do not have the ability to be on side court, then you are going to need longer focal lengths. If, for example, you have the kit lens RF-S 18-45 STM, then you would want to consider the RF-S 55-210, (on the Full-frame cameras they use that's like a 88- 330mm) which you can get from the Canon Refurb store (good as new, come with a Canon warranty) for $280: Refurbished RF-S55-210mm F5-7.1 IS STM (canon.com).
That said, the techniques they use are interesting so among the range of information, I hope you will find some good advice in here.
I strongly recommend using Back Button Focusing (BBF) in conjunction with Servo focus and face/eye detection for people. See the following video from Canon on how to set BBF up. Note that Servo focus is initiated.
I personally use single point centred spot focus assigned to the AF-ON button, and I use single point, centred exposure assigned to the * button (the default). This allows me to precisely set the exposure I use the SET button to centre the focus point, so I can keep the * button for exposure lock. This takes some practise and the order of events goes like this.
Step 1: Find a point that has 18% reflectance and and lock exposure on it with the * button
Step 2: Find the face of your subject and TAP the AF-On button to initiate focus. Face/eye tracking should then follow them. If it does not, hold down the AF-ON button to track the face manually. If you need to re-centre the focus point, TAP the SET button.
Step 3: Recompose and shoot with the shutter button
You need to train for this, just like an athlete, and that means getting to know the layout of your controls so well you don't have to think about which button to feel for - that takes practise. Also, do not shoot using the rear LCD, use the EVF, particularly for long shots so you don't suffer camera shake:
At the end of a shoot, upload the photos to your computer - actually, taking the USB card out of the camera and using a USB card reader attached to your computer is the fastest and most reliable. When done, return the card to the camera and FORMAT the card clean with the camera's format command. Your camera is now ready for the next shoot. Do NOT use Micro SD cards with adapters, they do not work reliably with cameras.
