Mastering.
And additions. Right now, you've got a melody... and that's about it. with the exception of some background effects, which are fairly minimal.
What you need is to add at least 2 - 3 more instruments, a recognisable chord progression (that has at least one variation), harmonies, counter-melodies, and shifts to other effects on occasion.
Let me explain.
Your melody almost sounds randomised. The reason isn't necessarily because it IS randomised, but because there's nothing to back it up and provide any structure.
What you need to do is figure out what chords you're cycling through, and use those to add new parts underneath or on top of what you already have. What you have already sounds a little more like a supporting part than a melody, so I would suggest making at least 2 other instruments that also support, and at least 2 other instruments that carry melody (which HAS to change throughout the song!).
Some drums might be nice, too - I mean a real beat, not just background effects.
One note - mastering is possibly THE determining factor in what people think of your music. You can write good music, but what makes it awesome is how well the music has been mastered to sound "professional". But that just comes with practice (and looking up tutorials online - which is how I've learned a lot of my mastering skills).
There's a lot more you can do, too... but I think that you'll learn with experience.
This reminds me a lot of my earlier stuff, which is why I'll make you the following offer: I'll take this song and transform it completely just to show you what I mean, and to give you some building blocks to help you make your music better. But I have to get a response from you to know that you would be cool with me doing that.
btw, if you take me up on my offer and you happen to be using Reason 4.0, let me know (it would make it a lot easier for me).
Don't take the 7 too harshly. I don't give high grades easily (don't be fooled if you check my other reviews - I usually don't spend the time writing reviews for things I think don't deserve commendation). You've taken a critical step just to get this far, and I do see a lot of solid potential in your work. As just one example of that, you have a great sense of the flow of the music. And that's one thing that I had a lot of trouble with personally.
But I think that's enough for one review. Let me know if you're interested in my offer.
Power to you, StarScythe!