If you desire to mature unto the deeper side of prayer, the key is to understand that prayer is an outflow of your knowledge and devotion to God. Prayer is not just an activity, it is more like an expression of something deep within your soul. We find some of the most profound prayers in the Book of Psalms, you see the Psalmist giving voice to, and expressing something deep within. You cannot pray effectively or get into the deeper side of prayers if your soul is empty. A merely religious obsession with prayer without giving thought to some of these nuances leads to shallow, powerless, useless and often misleading prayers.
One of the most important characteristic of deep prayers is that it is driven by deep knowledge. Prayers, meditation and contemplations are not the forte of the ignorant person. There is nothing to pray about because they do not know what to pray about. You cannot pray effectively from a place of ignorance. This is why the disciples famously asked the Master to teach them how to pray; they were clueless as to what to pray for and how to pray for it. The Holy Spirit does help us to pray when we do not have enough knowledge as to understand what to utter, nevertheless, as you pray in the spirit, you would be led into the Word and better knowledge.
So, you should study more than you pray, and to keep an effective watch, you should never pray for less than an hour every day. A watchman that spends time reading, studying and thinking through issues is like a shotgun that is locked and loaded, ready for action.
The good person out of the good treasure of his heart produces good, and the evil person out of his evil treasure produces evil, for out of the abundance of the heart his mouth speaks.
Luke 6:45 (ESV)
Deep, effective prayers are not determined by how much you shout, but by the quality of your mind. You should be ready to mature and grow enough potency within your spirit to spend 2 to 3 hours everyday praying, meditating and contemplating over matters of your watch.