I've got a lot to learn about mixing so I won't get into that.
But composition-wise I would take time to make clear to yourself what the story is you want to tell. This can be totally instrumental.
Which riffs are essential, what drumparts are vital. What melody should I hum when I have this song in my head. What moment in the song do you want your listener to react emotionally to the song, what kind of emotion should that be. Things like that.
Once that is clear to you start to clear away everything that doesn't help telling the story.
To me there are to much parts in the song that aren't telling enough story. And are thus not interesting to listen. While some other parts are not getting the attention you would like them to have. A thing you could do is cut it into two songs. With one or two bars pauze in between at 5:50 after that break I would let it die away, then start a new track and go on with the next bit. To me this last part feels totally unrelated to the first 2/3 of the song.
So, like Bulls hit said, strip to the essentials.
A side note: I don't like the timing in the drum parts, the drum track doesn't feel alive. But this happens often with samples, which I guess these are.
