Hire a coach. All you're going to get is people posting the exact same pics and links about how your serve differs from the pros. What you really need is for someone to look at it in person and tell you how to make YOUR serve better, not make it more like a pro's. It also doesn't help that all we've got to go on is six serves on a shaky camera.
And even if that's your own court, please put on a shirt.