My hair will not hold curls?

Seperate your hair into peieces thin peices if you have thin hair and it wont curl, and before curling the hair take a section or piece of hair and twist it then apply it on the curling iron hold it for about 30 second and reapete if needed, instead onf putting hair inside the curling iron twist it on top(: thats how i curl my hair and my extensitons and it sure seems to work, so if you haven't tryed that method consider trying it.