The fastest way to color in psp6 that I found is to make use of the draw tool again. If you go to the draw tool options and change the "stroked" option to "filled", you will be able to use the draw tool, as before, when doing the outline, only now the area formed by the closed curve of the outline will have the color that is selected by the dropper tool. To select the color, select the dropper tool and right click on the color you want on the original pic, or click on any color of your choosing in the colors window. I suggest doing it on a new layer, move this new layer below the outline layer by going to Layers/arrange/move down, this way you will still see the outline while coloring.

Here are various stages of me coloring the pic according to the original, or at least an attempt to do so, as I was not very faithful to the original pic.

First do the basic colors, no shading yet.

Now begin to do the finer coloring details, such as the effects and glows. I will describe how I did these below. Also, as you color, do so on new layers, since later we will need to smear (or make less transparent) the colors; this way the smudge won't involve colors you don't wont to be effected. Once you are satisfied with how it's done, merge that layer and the rest of the pic, by going to layers/merge all, or keep it as separate layers if you think you will change it later, but remember that too many layers can eat up a lot of memory. My pic had 10 layers and something like 12+ megs at the final stage; not a very good practice.

I left the pic alone for a while (few weeks) and when came back to it again, I added some more effects and tried to make it a bit more faithful to the original pic, the final version is at the beginning of this tutorial, still unfinished

If you are feeling bold, add some effects to the pic, something like this maybe (again, I will explain how I did these in the next section)

Or like this (actually same as the one above only with some filtering and manual retouching)