DON'T. Thin hair for almost any curl messes up because it'll frizz beyond control. Instead, search this site for your type of hair care. You have a wonderful hair color that looks great in curls. My cousin has your hair type but since she's small her hair isn't as long.
I use light shampoos only on weekends [Johnson and johnson]. During the week, I use soft conditioners like Dove. I use a paddle or vent brush [not boar] as I bathe her because curls work best in water. Then I just pull it back out of her hair while it's manageable.
again, she's little so I don't really style it. But this site offers great products per hair type. explore, talk with others. But thinning is the worst. it isn't worth it.