So a few tips that you might want to try when doing this Rihanna style include:
1. After you have round-brushed the Pompadour section of the hair, you can go through and curl small sections backwards to create a emphasis on the wave of the style.
2. Use a sticky wax to help keep the hair together when you are pulling it back and twisting into the roll on the back of your head.
3. If you are having difficulty with the twist, a braid will work as well. Just make sure to cover the braid when you are brushing the top section of hair back.
4. Dry shampoo is another product that you can use to help yourself achieve the fluffy texture on top.
Things that I would not do with this style are:
1. Do not overly tease the top section of hair. No one want to look like they are walking around with a rats nest on top of their head.
2. I would stay away for any pastes or waxes that are to matte since you really want to amp up the shine with this look.
Good luck and let me know how your Rihanna look turns out!