Olaf - what sports are you trying to shoot, and who are you shooting them for? are you shooting them for yourself, or for other parents? also, what ages are the kids you're taking?
the article linked has some good points, but the authoris being very general and has actually made a few mistakes. for example, he's talking about sports illustrated and taking photos of Barry Bonds from the third base side - anyone who has looked at SI photos would know they seldom publish photos of batters waiting for the pitch. instead they generally show the photo after the ball has been hit *from the batter's back*. you would instantly recognise this shot - you can see their number, name, face, and generally the one hand on bat (all the way around) and one hand forward with their face looking where thy've hit the ball.
the reason i'm asking what age is because the style of photos you take of someone playing baseball/T-ball at age 6 is very different than what you'd take at age 12.
if you are taking photos for other parents, you have to take photos featuring their child *as they see them playing*. if you're taking soccer, you will want a photo of their child with the ball and near another player - posibbly fighting for control of the ball, or taking a shot. if it's gridiron, then you want a photo of them doing the appropriate action for their position: a key block, running around a blocker, making a tackle, breaking a tackle, etc.
in the article, they have a nice image of the box of balls. it would be a nice image for the club, a yearbook, or newsletter/newspaper, but it's not something parents are going to be interested in. again, it all depends on who you're shooting for.
there are other moments that parents appreciate as well. if there is a child who has a sibling on the team, then capture them together talking or playing together. if a child likes to run around and dig in the dirt during a game (every year there are a few of those

), it's something the parents will appreciate at the end of the season. out of the hundreds of photos of my boys playing rugby, my favourite is from 3 seasons ago, where my younger son played up with his older brother and they are tackling someone together.
the shots themselves are very important. we constantly see photos of sports in the paper, on the web, and in magazines. what typically makes these types of shots somehow different from the shots we take of our kids can be summarised in 3 points:
- background. cars, rubbish bins, fences, lawn chairs, etc. are distracting and generally throw off an otherwise good photo.
- cropping. a long lens means you can fill the photo with your subject. but if you don't have a super long lens, you can still crop the image accordingly. if you have a dslr, try renting a long lens for a game day
- horizon. kids are as tall as we are. if you're standing on the sidlines taking a photo, you're looking down and the horizon will generally be above their heads. if you sit or kneel, you can move the horizon close to their waist level (or lower). i shoot this way for kids *and* big leaguers.
at the end of the day, experience will contribute significantly to the photos. just keep shooting!
btw, there are some really good examples in the September Assignment: sports thread.