In chapter 3 of Keller’s book, Prayer, he notes how prayer has been defined and understood by different religions and cultures throughout history and around the globe, and then succinctly sums up spoken (external/prophetic) biblical prayer…
…It mixes meditation , petition and thanksgiving, confession, and adoration all at once. Indeed, in prophetic prayer the forms stimulate and deepen and lead into one another.
And then Keller goes on, after some analysis of internal (sometimes called “mystical”) and external (sometimes called “prophetic”) prayer, to define it…
With all this in view, we can define prayer as a personal, communicative response to the knowledge of God. All human beings have some knowledge of God available to them. At some level, they have an indelible sense that they need something or someone who is on a higher plane and infinitely greater than they are. Prayer is seeking to respond and connect to that being and reality, even if it is no more than calling out into the air for help. That is, I believe, the common denominator of all human prayer. However, because our definition understands prayer as a response to the knowledge of God, it means that prayer is profoundly altered by the amount and accuracy of that knowledge. While everyone may have a sensus divinitatis, Calvin observed that we all refashion that sense of deity to fit our own interests and desires unless through the Spirit and the Scripture our view of God is corrected and clarified.
Keller, Timothy (2014-11-04). Prayer: Experiencing Awe and Intimacy with God (p. 45). Penguin Group US. Kindle Edition.
Try this: Find a quiet place. Open a Bible to Psalm 23. Read it slowly and while you do let the truths that are plain impact your mind and heart. Now, read it again, slower, stopping on occasion to express out loud with words what you now know to be true about you and about God… Ask of him and be thankful to him in the process. Pride is the only wrong in this space. In humility, connect with God, with whatever thoughts and words you have. You’re praying.