There are two types of kavana. The first is general – having in mind that one is standing in front of the King of kings and intending to pray with reverence and love. The second is particular – paying attention to the meaning of the words one is saying.
People are very different. Some find it easy to concentrate while others find it very difficult. Their minds are always jumping from subject to subject. There have even been great sages who found it difficult to concentrate on praying, and who reported how their thoughts would wander. Therefore, even someone who is daydreaming through most of the service should not give up hope; rather, when one notices this, one should focus on whatever prayers are left. We should not say, “If I can’t focus, it’s better not to pray.” For the very fact we are trying to stand in front of God and pray is already expressing something very profound – our wish to connect to God and pray to Him.
God assesses each person based on his or her temperament. It is possible that someone who finds it difficult to concentrate, but nevertheless manages to focus on a few blessings, is in a better place than someone for whom it is easy to focus throughout the service. Furthermore, those who generally have difficulty concentrating may be the ones to experience certain golden moments in which they soar and become incredibly focused.
The holy Arizal is quoted as saying that kavana is like wings, propelling prayers upward so they can be accepted. A person who prays without kavana, is expressing a wish to connect to God just by saying the prayers. However, since those prayers lack wings, they cannot ascend until one does pray with kavana. When this happens, all the prayers said without kavana ascend as well.