You could try the CG method, which is good for dry hair. I don't know what it does to curls as loose as yours, but it made my hair more curly.

Do you do deep treatments, intensive conditioning with heat? I did them once a week, and also did a hot oil treatment once a week, and after about 9 months my hair was so completely saturated that I didn't need to do them anymore.

I'd also say lots and lots of moisturizing conditioner left in, except that your curls are so loose my guess would be that too much leave-in conditioner would weigh your curls down.