Thanks, folks.
I just did another two, going smaller this time. I still have some work to do as far as making nice-looking starfields, but I'm getting there.
Now, I have a query for you smart people out there. I'm having an issue with painting the black over other colors. For some reason, the black paint breaks, and there is something of a bubbling effect that happens. No matter how much black paint I spray, this happens. The paints are definitely all of the same type (enamel spray), but even when I used the same brand of black as the colors, this was happening. You can see the effect in the picture labeled "My Very Second One" photo at the Flickr link in my first post, if you look around the moon.
Any ideas what might be causing it, and what I can possibly do about it? Thank you!
EDIT: It could just be the quality of the spray paint, now that I think of it. I started out using $1 cans of whatever I could get at Wal-Mart. However, in order to fill out some of my color palette, I ended up having to buy $3 cans of Rust-O-Leum. Well, let me tell you, I could immediately tell the difference between the two in quality: the Rust-O-Leum went on a lot better, smoother, and faster.
So it could be, I just need better paint. For now, though, I think what I have will be fine for practicing.