Does natural hair stand straight up or stick out to the side instead of hang below? Lots of people who are natural have this same problem. If you are not going for the afro look, this can most definitely be annoying. Here are a few tips that I use in order to get my twistout or braidout to hang.
Style hair when wet. The water molecules will hold on to hair strands which causes it to have a bit of weight on it. This will allow your hair to already have the "hang-time" you want before product is even applied.
Use a heavy product. Try styling with Shea Butter, Shea Moisture's Curl Enhancing Smoothie
or a thick leave- in conditioning cream. The weight from the product will help mold the hair into shape even before it fully dries.
Style your hair in the direction that you would like your hair to fall. Do not start braiding or twisting toward that back thinking that it will hang toward the front. This plays a big roll for those that style toward the root, which I do. If you twist/braid tightly at the root that direction plays a key roll in how the style will fall.
Use a satin or silk scarf instead of a bonnet. The scarf can lay down your roots and hair strands in the way you would like. If a bonnet is worn, hair tends to shift around a lot.
Use bobby pins to help assist you in flattening your hair. Pinning the style to your head with little force works wonders.
The moisture level in your hair also plays a key factor here. I notice that if my hair isn't properly moisturized, it does not "lay down." Try the moisturize & sealing method.