Tag ’em low
This is one of those little things that can make a huge difference in a game. It’s the sort of thing every fielder should know, but many either don’t know it or forget about it.
When you’re making a tag, always try to apply it low, down near the feet. You’re far more likely to get the call. From an umpire’s point of view, a high tag (around the head or shoulders of a sliding baserunner) often implies that the runner slid under the tag. Now, that may not be true — the player may have applied the tag before the runner reached base — but it doesn’t matter. That’s what the umpire will see.
If you apply the tag around the feet or ankles, however, the appearance is you got the runner before she got to the bag, and she’s out.
Wherever possible, apply a low tag. And don’t forget to sell it at the end. Hold the ball and glove up high, show it to the umpire to say “see, I got her!”