“Pray without ceasing” (1 Thess. 5:17, KJV).
I recently received a Facebook message from a student who had experienced a drop in her commitment to God and spiritual growth. She requested my advice, asking how she should get back into a regular practice of prayer. Below is a part of my response. I pray that others might find some help in my ramblings.
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Concerning your prayer life, I can somewhat understand what you’re experiencing. Although I have never been nor ever will be in your exact situation, I’ve been through several times in life when I felt that I didn’t know how to pray. Here are a few suggestions, for whatever they’re worth.
First, ask God to guide you in your praying. Confess your neglect, accept forgiveness, and invite divine strength to persevere in your spiritual growth.
Second, pray even when you don’t feel like doing so. Setting a specific time each day to pray can be helpful. Set a time and stick to it. If you can’t think of anything to say, just listen…or read scripture. (Some Psalms might help.) Music has also served as a helpful aid in my times with God, and sometimes I like to spend time somewhere in God’s nature and let whatever I see or hear lead me to commune with God–listening, observing, maybe talking a little. Prayer is not always talking.
Third, consider using prayers written by other people of faith. There are some books of Christian prayers. One guide for daily prayer that I learned about just today is The Divine Hours (3 volumes) by Phyllis Tickle. A related book that I plan to read soon is In Constant Prayer by Robert Benson. There are some other books that have benefited my spiritual walk during the last decade, and I can recommend some of them to you if you wish. I know you have a lot of reading to do for classes and therefore might not want to read other books, but I also know you like to read. 
Fourth, spend time with people of prayer. Listen to their prayers. Let their prayers become your prayers. Ask them to pray for you and your prayer life.
Fifth, know that I am praying for you.
One thing you could also suggest is The Jesus Prayer: Lord Jesus Christ, Son of God, have mercy upon me (the) sinner.
Based on the Prayer of the Publican (Lord, have mercy upon me) and the Blind Man (Lord Jesus Christ, Son of God – have mercy!) I love it for its simplicity and how it does greatly assist in fulfilling the command to pray without ceasing. As I go about quieting my mind or find my mind filling with thoughts that are far from charitable – I’m getting better at jumping to this prayer so my mind will be closer to where it needs to be by God’s grace.
Blessings to you!