A couple of tips which I hope will help you. My first post on the site
Don't be afraid to up the ISO to the limit. I regularly shoot at ISO 400 in good/slightly overcast daylight when shooting football. Sharp but with a bit of noise is far better than soft/blurred. A properly exposed high ISO image will have surprisingly little noise in the main subject area even at ISO 1600.
eg. a night match from last season
taken at 1/320 at 300mm f2.8 at ISO 3200
When setting up look at sun/light direction and wind direction. Try to get the wind behind you (tip: check the corner flags). Avoid shooting directly into the wind as dust (if it is dry) and water (if it is wet) will quickly get onto the lens front element. Get the light behind you or at least offset by 45 degrees. This will ensure the players faces are not in shadow.
Try to pick positions with interesting backgrounds or at least backgrounds that will not interfere or detract from the image.
Don't try to get all the action. Get the action which fills the frame at the focal lengths you are using. In the 90 minutes of a game there will be plenty that will come your way.
Use manual exposure and meter off the grass and then adjust to taste. If the light is changing strongly (sunny day with clouds passing in front of the sun) then go to AV mode. Save TV for waterfalls
For day time matches aim for 1/1000 plus for shutter speed and lens wide open minus a half to a full stop (eg. if using a f2.8 lens then set it to f3.2 or f4). For evening you want the lens wide open (ie. f2.8 if it supports it) and up the ISO until you are getting a shutter speed at least equivalent to the reciprocal of the lens focal length ie. if using a 200mm lens then you want at least 1/200 as a shutter speed. Ideally get at least double the minimum shutter speed.
Use centre point focus and AI Servo (or your cameras equivalent). On the 20D you are using you can assign the * key to act as a focus lock button. This allows you to focus and hold focus for events such as free kicks and penalties.
For daytime matches shoot large fine jpeg and auto white balance. Same for evening matches but use a custom white balance. Raw has its place and uses but if you are going to select 100 shots from between 800 and 1500 shots four times a week and then edit the selections you will quickly save raw for team shots and presentations.
Football is about timing. Once you get a feel for how far a goalie kicks then you will be anticipating where the ball is likely to go and will be able to get the headers, contacts etc.
I rarely shoot bursts of shots even though I have the camera set to its max fps. I rely on timing and will generally shoot one frame and very occasionally two frames.
Watch the horizons. It will save you a lot of time in post processing if you keep the horizons level.
Use portrait mode as a general preference and switch to landscape mode as necessary eg. when trying to get a goal area shot.
Hope this helps.
