I carefully choose the tiles to make sure there are no pre-existing chips.  I then wash them and dry them and put them on a clean, flat surface.  Keep in mind, this process can take place on any color glazed tile and also on any type of glazed item.  I did two soap dishes for this project.  (bottom left, plumerias)

Then I draw my designs with a dry erase pen.  It is very easy to accidentally erase the entire design, so it is good to try to glaze them as soon as possible.  

 

 It is also good to keep little helping hands away from the tiles at all stages! 

Once my designs are drawn and the dry erase pen has completely dried, I begin "painting."  What I actually do is use an eye dropper to apply the glaze to the tiles.  Sometimes I will use a paint brush in a tiny area.  Otherwise, all of my "painting" is done with an eye dropper.  I do one color at a time.  I start usually with the color that will appear the most.  With this project I began with orange, then yellow, and then dark gray.

 

Next I added light gray and green.

 I have finished the painting and am waiting for them to dry.  You'll notice the yellow tropical flower in the second row from the top is missing the dry erase lines.  I have wiped these lines off to get an idea of what it will look like once it is fired.

 

Here is the finished product: these tiles have been fired.  In the firing process, the dry erase marker burns off.

This is the bottom of the soap dish, so this is what you would see while lying in the bathtub.

And this is the top of the soap dish.

Here it is installed in the shower.

And here is the shower!