I have very straight hair so figuring out how to take care of my daughters hair was quite a challenge. She has 3b-c curls (http://www.naturallycurly.com/hair-types). Most advice for biracial hair doesn't work on her because her hair is very fine & not dry at all. Through trial and error and a lot of internet research, here's the routine and the products I use on her:
For starters I CO (conditioner-only) wash her hair. To CO wash, you first have to get a silicone-free conditioner (Suave & V05 are popular - I've found Suave is better for fine hair). You wet your hair & then apply generous amounts of conditioner to the roots & massage in (you can't apply too much. Use enough to make sure your hair is evenly coated). Let it sit for about 5 minutes or so. Rinse out really well. You can follow up w/a more intensive conditioner on the ends but for my DD, since her hair is so short & she throws a fit when I wash her hair, I skip the heavier conditioner & use a leave-in when she gets out of the tub.
I use Garnier leave-in conditioner on her hair. It helps get the knots out while combing too.
Then I apply one pump of Paul Mitchell Skinny Serum, which helps to tone down frizz.
Then I scrunch in some Herbal Essences Totally Touseled Mousse to give her curls some hold.
When I need to perk up her curls (they get messy very easily since she's a toddler) I use the following:
Johnson & Johnson's Detangler to help me get a comb through her hair (Note: I always use a wide tooth comb on her hair).
Then I use plenty of water to wet her hair to help it curl up again. If she's just wearing it natural (not pulled back) I might scrunch in the HE mousse or whatever gel I have on hand. If I'm pulling it back I use a boar-bristle brush like this:
The brush needs to be very densely bristled so that it has a smoothing effect. I usually use some gel (yes on dry hair but just a bit) to help it stay & not immediately get the "halo" look.
Now you obviously don't have to use the products I listed above. Most of them I already had on hand for myself (I'm a product whore) so its not like I went out & bought tons. But give this a try. Not all biracial hair is the same and putting tons of oil/grease in hair that doesn't need it is *not* a good look.