I don't like this sig much, i'll give you some pointers.
The sig as a whole is too plain, it's just Eminem on more a less a plain black background, it needs to have some flow going on, but also it has to be more interesting to look at.
Eminems face looks too sharpened, so if you go edit, fade sharpen, and tone it down a bit that should look better.
The lighting on Eminem himself is decent. The text is shocking, i'd reccomend usng a smaller text, and use Mountain Drew's sigs for text inspiration.
The white border doesn't really fit in with it, so after you've spiced up the background just use a black one, hope i helped.