I have no idea of how it works

I have tried a lot of manifestation, but, for what I remember I just got 2 successful manifestations, the first one I just lie down in my bed and imagine me eating grapes to manifest it because I didn't eat it for a long time, ok, next day without doing more anything my grandma gave me grapes! and the second manifestation I was leaving the bathroom when I remember a girl that I have as a friend when I were younger, I remember that I miss she but this time I was like: "meh, she was cool but if I never see she in my life again I'm OK too" and I think I have tried to manifest see she again but I don't even try, it was probably less than 10 seconds and in the next day she got my number I don't know how and she refuse to speak how. Also I have sometimes got some will for something to happen and without doing anything God gift me

So, manifestation just worked when they are not something you care too much? my others manifestations I was not that persistent but the ones that got right just take one day, how could I improve my manifestation?