How long have you been practicing it? (the correct answer is not enough)
In all seriousness, just keep practicing. Watch the video again. Follow every instruction to a T.
Practice in a mirror.
Most importantly... If you have a laptop with a camera... or any recording device... videotape yourself doing "Bullet". Wait a few days or so... record another one, wait a few days and record a third video, all of you just doing bullet three or four times or so. Practice everyday in between(obviously). Wait a few days and watch each clip in chronological order.
You'll quickly realize it's a lot better than you think you're doing.
The same thing happened with me, I didn't think I had enough 'flair' when doing bullet, but I just kept practicing.
This method is actually what I use when learning any flourish.
Hope I helped.