Help
Okay I decided it would just be easier to do it this way and start from scratch ^^ I'll cover the basics of your image, layers, and coloring, and anything else I decide to throw in ^^;
Starting From Scratch
You want to start with a blank image. Here's a very important thing about computer images. Now it all depends on how big you want your image, now the size I want to finish with is 150x150, I'm going to start with an image the size of 500x500. The reason for this is when your done, you will resize the image to the size you want and it will cause the lines and colors to blend. So make your image fairly big, since my target size is small, my starting size is small. But if you were working with a normal artwork you would probaly want your starting size around 1000x1500 and you would resize it to 800x1200 or 500x750, just depends on the size you want.
So now you should have this:

Your layer pallette and your tool options should be open, if you prefer the overview window or anything else to be open, that is fine, these are just the main two for now.
Now, to start the image. Right now we only have the background layer, so we need to create a new raster layer before drawing. Go to your menu, choose layers, and then 'New Raster Layer'.

Set your preferences like so:
Name: Lines
Blend Mode: Normal
Opacity: 100
Group: 0
Layer is visible: Checked
Lock Transparency: NOT Checked
Mask is Enabled and Locked for this Layer, both should be checked
These settings should always be the same when creating a new layer, except for the name. You don't have to name your layers, but naming helps keep track for now. Lines is your top layer, always, unless you want something to overlap your lines. Now you can begin drawing, use the 'Paint Brush' tool. Hardness, Opacity, & Density should all be at 100%, I suggest using a brush size of 2, but if you want to try smaller or bigger, it is up to you. Go ahead and start drawing(I suggest drawing a human to follow with this tutorial), but make sure your on the Lines layer, and if you have to erase, use the eraser tool.
This is my finished drawing:

I shrunk that, the original size would still be 500x500, but just to make it load easier, I shrunk it. I will admit, I cheated and scanned an old image in, so that would be why my lines are all different sizes. Once your done with your drawing, move on to coloring.
Side Tip: One thing that really adds to pictures is how you do your line work. If you look at the image above you notice I use thin lines. Now I will point out, I outlined the image with a thicker line, you can see this really well on her hair. Try it. Leave your detail lines thin, and go around the outside of the image with a thicker line, maybe 2 sizes up. Just the outside lines, leave the inside lines alone.
Coloring
Once your done with your lines you should be here:

Now we will start the next step to your picture, the coloring. Coloring is very important, so be sure to use colors that blend well, hot pink and red are not not a good idea O.<
So let's get started. First, go to your layer palette, and choose the 'Background' layer by click on it. You are not going to color on this layer. Now create a new layer just as before, but this time the name will be 'Hair'. Your layer palette should look like this now:

The rest of the layers will be added in the same way, always building below each other, but I'll continue on that later. Now choose whatever color you want for the hair, I suggest not using black or white, as they will make the coloring alittle difficult. I'm going to use a soft blue color. Use the 'Paint Brush' once again, and set the size fairly high, my brush size was '36', do it can be big(As always make sure your on the correct layer! Right now your on 'hair'). Your coloring does not need to be perfect right now, here is an example of how things will probably look.

It is okay for it to be this way. Now, once the hair is colored, go back with your eraser and erase all the excess coloring. Anything thats is overlaping onto the skin area or background area should be erased. Once all the erasing done, it should look more like this:

Your done with the hair, for now. Next move onto the skin, create a new layer below the hair layer. Color every skin area just as you did like the hair and erase all the excess coloring. Now be sure to color over they eye area, I know it sounds wierd, but just go ahead and do it, I'll explain later on.
Side Note: ALWAYS create the hair above the skin, never put the skin above the hair, because when you get to the eyes, it can cause problems.
Your image should be at this stage now:

By now you should have the hang of creating layers and adding color. Go ahead and add clothing color, accessory color, ect. until you have the base color for every part of the image. Don't worry about the background right now, we'll save it for last. Now once you have all your colors, the image should look more like this: (image shrunk again)

Now comes the fun, finally time to add the shading. If you've ever studied shading, then you know about direction and such. But just in case; When you shade you have to imagine where the light source would be coming from. Imagine it like a lightbulb hanging from the right corner of your picture, and then determine what the light is touching, and what the light can't reach, which creates shadows. So let's get onto the coloring.
First off, here is a very handy short-cut. Do you know where to 'Retouch Tool' is located? It looks like this
, find this icon on your tool bar and select it. Your Tool Options window should look like this now:

Here are the ones you want to remember: Darken RGB, Lighten RBG, Lightness Up, & Lightness Down. You will be using these four throughout your coloring. So now to the hair, choose the hair layer, and set the Retouch tool to 'Lightness Down'. You may mess with the settings all you want depending on how you want things to work, Size depends on the hair space your coloring. I have my hardness at 24, opacity at 7(you don't want the color to bright, try setting the opacity at a number and then test it on the hair, if it is to dark, undo and try another setting), step is 11, and density is always 100.
Now I'm imagining the light is coming from the upper right side, so I'll begin by shading her left features first. Once your done with the shading your move onto adding the lightness, choose 'Lighten RGB' and begin coloring on the areas where the light would be touching. You may have to play with the settings once again, just make sure your hardness is lower than 50 at the least, and it may be worth it to keep the Opacity at 100, depending on how hard you want to lighting affect to be. You may need to switch back and forth between Shading and Lighting to get things correct, just be sure not to over do it or the coloring will get messed up. Once your happy with the shading it is time to add the hair "shine", every anime character has that special little shine. Now there are two ways people like to do this, some people just like a straight shine, which is what you'll get first. And then other people like the jagged shine, which with a few extra steps you can get. Once you have added the normal shine using the 'Lighten RGB' setting, lock your layer. This can be done by either clicking the lock for the hair layer on the layer pallette, or by double clicking the hair layer to open the options back up and selecting 'Lock Layer Transparency'. Once your layer is locked, go to the tool options palette for the 'Retouch' tool and choose smudge. Your settings should be, hardness below 50, Opacity 70, and step 1. The size is according to how big you want the jagged line, you can test different sizes until you find what you like. Start from one end of your shine and move the brush up and down while moving across it, don't move to much, just enough to get the effect you want. Then Your done with the hair. Below is a chart to show my process, in case any of this was confusing.

Your done with the hair now.
Next will be the skin, but I have to point out another step I'm taking. Her top has that black mesh sticking out if you noticed, but in this picture:

The mesh was colored completely black. Now I need to make it lighten up, so it keeps a mesh effect but at the same time you should be able to see the skin below. I made a 'Mesh' layer and had it set atop of my skin layer so it would over lap it. Now I changed to 'Mesh' layer from a normal layer to a multiply layer and dropped its opacity to '40'. Thus I made it slightly translucent, right now it just looks like a darker color, but once I add my skin shading you'll be able to see the difference. This trick could be used for different things, I used a multiply layer, but you could use a burn, dodge, difference, ect. depending on the effect you want.

Okay, now the skin. Back to the retouch tool, this time select Darken RGB as your tool, this will be the shading on your skin. And then 'Lighteness Up' will be used for your shine. If you like how Lightness Up/Lighten RGB look instead, then you could use either of those. By now you should be far enough along to set up all you settings how you like. Once your skin colored, it should look simular to this:

I guessing this far along, you've gotten down how to do it all, so I'll stop explain coloring here, heh. Now I'm just going to say, "Go through all your layers, except for the background, and add the proper shading, once your layers are all shaded, we'll continue". Once everything is shaded it should look something like this:

Notice the shading on everything, including the bubble gum, all the details have to be touched. I used Lightness Down and Lighten RGB to do all my coloring here, just because I prefer it, so you use the tool you prefer. Now you have probaly been wondering about the eyes right? Now it is time for the eyes! This is one of the final step I usually do.
Now, you need to create a new layer over the skin layer, this is going to be the white area in your eye, you can name 'eye whites' or whatever you want. Using white and the paintbrush tool, fill in the area that would contain white, go ahead and fill in the whole are, like this:

Then use one of the shading tools to add shading on the top of the eyes.
Now, create another new layer over your current 'Eye Whites' layer, this will be your 'Eye Color' layer. Color in only the areas that need color, and be not to color over your shine, it should remain white. You should now be here:

Now it comes to coloring the eyes, use the 'Retouch Tool', My choices are Lightness Down and Lighten RGB. You can experiment and color the eyes how ever you like, I do them like this:

Once your eyes are colored you can call it done or add an background. I'm not very good with backgrounds so I usually just leave it a plain color or add fun designs. Any background designs should be done on the background layer or the bottom most layer. I added a plain lime-ish back ground, and I'm going to leave it at that, if you want to do something special go ahead.
Once your done with the background, it is time to finish this up. The first step is to merge all your layers into one layer. Go under layers>>merge>>merge all(flatten) and this will push them all together as one layer.

Now it is time to resize the image, causing everything to blend. This all depends on the size of your image and how small you want it to be. I would try to take it down atleast 350 pixels. Now to do this go to Image>>Resize... or push Shift+S for PSP. Make sure Maintain Aspect Ratio is checked and it set to 1.0000. Once you lower the width the height should automatically adjust, my image is a perfect square to it goes from 500x500 to 150x150. It comes out kinda like this:

Now you are finished. But I for a special touch like to add a border around my picture. Set the background color to black then go to Image>>Add Borders and set the size to 10 on all sizes. And that does it, you now should have a finished image.

My Finished Image
I think I covered everything, practice with it often to get it all down. Also bookmark this or copy it onto your computer for reference. If anything didn't make sense, 'Note' me on DeviantArt, and I'll see if I can break it down easier. Also, when you start inking and scanning, send me a note, and I'll explain how to prepare an inked scan. Good Luck!