Opportunites

Here I am again with more questions than answers, that's starting to feel normal for me lately, maybe this how it's always meant to be.
Anyway I've had some great opportunites to pray for people lately, I'm still waiting for the right time with the student from school, but other people have agreed to prayer.
I don't quite understand though, each person felt something; one said it's like there is an electric blanket on my back; another said that she had electricity from the top of her head to the souls of her feet while another said she was tingling all over and seeing colours in front of her eyes (that one is new for me) but after having prayed I could only see miniumal difference in each person, now that's why I've got questions.
I don't understand why there can be such manifestations with so little result.
There is much to learn.