I wish I could watercolor, I always end up ruining the lineart :c Very pretty!!

Do the lineart with any ink you like, then try scanning and painting over the printed copy! My HP printer's black ink doesn't run with water.
OR, like i did here, take a colored pencil (a brown polychromos in my case) and do the lineart with that. It never runs, and it's thick, so the paint doesn't reach the colour on the other side and you avoid ugly stains c:

Another good idea is to paint each segment of the piece, let dry, then paint the adjacent parts. This way the different colours won't mix~

Thanks so much!! ;A; I'll try it!

you're welcome! i hope this was useful c:
when you master watercolours, it's a very quick and easy technique to give some life to your sketches!