Watercoloring images can often be tricky. At my class I gave a couple of tips. Start light, you can always add color, it's a little more challenging to remove it. You're color will be darkest on the aqua painter when you first start so start in your darkest areas. Your colors will blend more if you're working with wet paper and wet brush. You can use a clear Wink Of Stella to color just like an aqua painter for a shimmery look, I love that technique the best! The most important part, have fun and practice. You will get better the more you do it.
I only used three colors for this flower, Melon Mambo for the petals, Old Olive for the leaves and Peekaboo Peach for the center. The more water you use the lighter you ink will be. Places I wanted lighter I used more water with my Melon Mambo. I also like to let the lighter areas dry and come in and do the darker areas later. Watercoloring is pretty forgiving, give it a try!!