My hair does not curl, i've tried titanium crawling wands I've tried ceramic curling wands I've even tried straighteners?

I don't know what to do, Is it my hair or is it that I just don't know how to curl hair because I've curled my daughters hair and her curls fall out too. I curl my extensions an The first time I curled that hair the curls stayed in but as soon as I dyed the hair and washed it I can a longer keep curls in my extensions either . Any suggestions would help what would be better for curling my hair and what products could I used to keep the curls in. I have straight thin fine hair, One lady even told me that my hair is baby soft like a babies hair. But I want curls..