Siman - Berachos Daf 15

• Washing hands before tefilla

Washing hands before tefilla is so important that one should travel back almost a mil and forward as far as a parsah in order to find water.

• Hearing oneself recite Krias Shema 

A significant amount of the daf focuses on the machlokes in the Mishna regarding whether one is required to hear himself recite Krias Shema to fulfill the mitzva.

• Pausing between words that tend to get attached

From the word "ולמדתם", “and you should teach them” we learn "שיהא למודך תם" ,“that one’s learning should be pure” (articulated faultlessly). Therefore one should pause between words that tend to get attached such as "על לבבך". (“ul levavecha”)