The best advice I can give is to find your own voice, and sing like YOU. You can use a vocal teacher to improve your range, breath support, and vocal strength. Don't try to sound like someone else - that's a cop out. Take what strengths you have as a vocalist and use that to create your own sound. If you must learn to sing like your favorite R&B singer, then that's what you choose. You can learn by listening to what they do, but by all means, please don't copy every lick and sound, because you will just lose your own voice altogether. I didn't listen to the stuff you posted yet, but I will as soon as my work computer decides to cooperate. If you don't have any experience in singing, you will definitely want to find a voice teacher that will give you proper technique. That's the most important thing if you want to sing for a long time!
Good luck!
Jen