I am 3c and i use things like argan oil, coconut oil, or jojoba oil, or tea tree oil. I also use the ACV rinse. This is a mix of apple cider vinegar and water with a splash of your favorite herb oil. I use it every time i wash my hair. It helps closes your cuticles, so your hair is a lot healthier, shiner, and stronger because it can hold and absorb more moisture.
Herbs and moisture are key to caring for your curls. I am a 4c and i use Just 4 Kinks (http://www.etsy.com/shop/just4kinks) hair butter and hot oil treatment for external use and i also drink their herbal tea for internal health 2 times per day. My cousin is also a 3b and she says it works perfect for her hair. I hope this helped.