Tagging Up, like base running has become a lost art but if you know what to look for it can be very easy to capitalize on. As we learned just recently can also win a World Series.
You must first understand how an outfielder is taught to catch a ball. Glove at eye level and behind the ball with their momentum headed towards the bag. Anything outside of this, run. The challenge is that you can not wait on your coach to tell you to go. In base running windows are short because you are capitalizing on the outfielder balance or lack their of or attention. By the time the coach yells go he has regained it.
1. 2. 3. Letters of jersey are headed away from bag. If you can't see the letters he can't throw you out.
4. Weight back with body in front of ball (not behind). Being lazy and has to go against momentum to throw.
5. Flat footed and still. Has to waste time to generate momentum to throw.
6. Behind the ball with momentum headed towards bag. DO NOT RUN!
Know the Why