PP Teens Contest - Unfinished

Here, I have added colors to the Powerpuff Teens. This is unfinished. This is not the actual submission for the contest. I will work on coloring details later.

ink: *greatLP
colors: me

I need to ask questions. How do I make the color smooth inside the lines? Like in Buttercup's hair, there are still some white and gray pixels on the inside edges of the lines. Is there a digital coloring tutoral at DA?

And also... how do I make links? I want to make a link to greatLP, but I don't know how.