The best tip i can offer for color is this.....

Never rely on your eye alone.
When setting out to color your cel find pictures 
or still shots that you like the color scheme of -
 regardless of the anime.  then print a color 
copy and mix your paint to match. Check your 
mixed color by putting a daub of it on your print 
out.  that way your never surprized by how colors 
look together.  
hope that helps!
Good luck & have fun!!