How To Curl Uncurlable Hair?!?

My hair is pretty long, but not too long, it is blonde and kind of of thin. it N.E.V.E.R curls, and it really makes me upset :[ i have all the curling sprays, mouses, and gels...i have tried it all. i also have 2 curling irons, hair rollers, and these bendy things you put in your hair. i was sort of going for the curly\wavy look, like selena gomez, or victoria justice. so i need help plz