First high quality Vector in years! Not to mention of using Pixelmator's vector the last time, it's function was really odd that each line is a new layer. xP
I used Inkscape.
Get a hold of use of that software, it's really easy to use and it's very smooth on the quality. The tools is quite weird, but I can manage it. All I'm missing is stars on her hair, sorry for the lack of that but hey. It's Luna, I'm using it as a personal avatar pic for the majority profiles I have around. :D
How I did it wasn't so effective, reading up on some tutorials on how other people use Inkscape to be more efficient on it and how to be clean on the vector lines. To continue making more vectors as I can. More of Luna coming soon! Couple ideas I suddenly got from watching the seasons again. |D

Vector done by me (c) Atalix Ruben Lujan
Princess Luna OC Belongs to (c) Hasbro
Software used: Inkscape