The best way to add power to your prayers is to use the word of God. Who else would have more power and truth than the maker of the Universe. Use His words to transform your prayer life and ultimately your life. 2 Timothy 3:16, All scripture is God-breathed and is useful for teaching, rebuking, correcting and training in righteousness.
When I find myself praying for the same things over and over again, I then begin to search for scripture to match my need. Or to be more honest as I catch myself acting less than righteous in the same area of my life over and over again. To create a prayer I take pieces from the scripture or the whole thing and with the power of the Holy Spirit a prayer is developed. As the Holy Spirit is at work within me the prayer is often transformed many times. I then pray this before entering a situation that would normally trigger my less than Christ-like behavior. Here is one of my prayers with the scripture listed after it.
Lord, I need you within my life, come to me, hear my voice and my inner heart. You know what I need while I struggle within my confused mind. Create within me a clean heart, I am not able to tame my tongue alone, keep watch over the door of my lips. Do not incline my heart to any evil thing. Help me to accept the corrections of the righteous people in my life. Jesus I ask for your transforming power within my life to create in me a clean spirit. Lord Jesus create a trap within my mind to stop my judgmental heart in its tracks, before out of my heart flows cruel or unnecessary words. Lord I ask You to govern my tongue in all situations to say the things I should say and to stop me from saying the things I shouldn’t. Thank you Lord for all the corrections You are doing in my life. I desire You with all my heart, and I surrender myself entirely to your control Lord Jesus. I love you, Amen.
Psalm 141:1-5 parts of: Lord, I cry out to You; Make haste to me! Give ear to my voice when I cry out to You. Let my prayer be set before You as incense, The lifting of my hands as the evening sacrifice. Set a guard, O Lord over my mouth; keep watch over the door of my lips. Do not incline my heart to any evil thing, Let the righteous strike me; it shall be a kindness, and let him rebuke me; (NKJV)