"11 Prayer is the medium of miracles. It is a means of communication of the created with the Creator. Through prayer love is received, and through miracles love is expressed." - ACIM
You enter prayer to experience and receive God's love and to thank Him for providing it, and then you fill up with that love, and then you overflow that love to others, which is an extension of love - a miracle. If you can't pray/commune with God and receive His love, then you cannot work miracles, because all miracles come from God.
Again, if you want to work miracles, you need to learn to pray. Miracles aren't just shifts in perception or changes or mind. They are what flows to HEAL mind when love is allowed, and their extension extends that healing to others.
If you are working with ACIM purely on a level of fixing thoughts and changing perceptions so that YOU are more at peace in ISOLATION, you are missing the point of what a miracle is, and the power that is being offered for you to share. You are working on healing so that you can become a medium for miracles to flow through communion/prayer with God, not just so you can float around the world in isolation being a bit more happy or less reactive. The purpose here is to learn to share in God's love and to extend its miraculous power to everyone.