When the Tefillah Flows
Rebbi Chanina knew his tefillah was accepted when the words flowed freely from his lips.
The Mishnah relates that Rebbi Chanina ben Dosa would daven for the sick and then say, this one will live and this one will not. Asked how he knew, he explained: "If my tefillah is fluent in my mouth, I know that it is accepted." The Gemara finds a hint in the verse in Yeshayahu that speaks of Hashem creating the speech of the lips and bringing healing. Rebbi Chanina did not claim prophecy. He simply paid close attention to his own heart as he davened. When the words came easily, he felt Hashem opening the way; when they stuck, he understood that the answer was different. His tefillah was not a recitation but a living conversation, in which a person speaks and also listens for how his words are received.
Source: Mishnah Berachos 5:5; Gemara Berachos 34b (on Yeshayahu 57:19)
Choose one bracha of Shemoneh Esrei this week, perhaps Refa'einu for someone who is ill. Say it slowly, word by word, and add that person's name in your own words. Then notice how it feels to say it. You do not need to read signs into your davening; simply let the words come from your heart rather than from habit. Over time, that one bracha can become the place where your tefillah feels most like a real conversation.