Honestly? That's pretty good~! The most important aspect I notice is that you seem to be pretty competent with your art, as shown here; everything in this picture is easily definable as what it's supposed to be, even if I had no idea what Touhou is or who Raiko is. I also appreciate your use of attractive colors here and the fact that you didn't make everything a solid color, as I see a gradient in Raiko's bass drum, which is an appealing sight.
If you don't already, I encourage you to draw more often~!
