okay, I think the quality isn't the best, did you do something to it?
Some advices: you shouldn't use that much outerglow on the starbrushes, it looks too thick and overwhelming. unless you want it that way of course =) other than that I tjhink the stars is placed alright, maybe a little bit crowded here and there, but that's just a question of personal taste, since you didn't go for realism.

as for the planets, I think that the biggest, orange/yellow one looks a bit low-quality, did you strech the texture or did the sphere-filter make that (since it in his tutorial)? And there is another texture in there in that same planet, which I don't think is blended godd enough, it would look better if it was mixed a little bit more with the rest of the planet. There are a few smaller planets that has too much outerglow, they should have less than the bigger ones. I'm not talking abou realism, I'm talking about what I think looks good. It's quite cool that you have made them in different colors, it makes the picture more alive. I hope that you're able to take this critique, but I'm not just criticising, I'm also giving you suggestions and comments =). I think this is good, and especially f it's your first try. You should keep on working on this one, good job. Did you lay down much time on this one ?, I think you did, which makes it even better in my point of view. Keep it up :lol: