This final step is always the scariest. After spending hours to get to this point in the painting, this last step can very easily ruin the painting.
The advantage of transparent watercolor is in the layering. The more layers the more the painting will “glow”. To obtain that glow, I mixed some acrylic Cadmium Yellow Medium with water and sprayed the entire painting with that mixture. After it was totally dry, I used a hair dryer, sprayed another layer, and then a third and final layer. If you compare step 5 to the final you can see how much more intense it is.
When the final layer was dry, I had to re-establish the white highlights to finish the painting.