Need Help with Technique!

Hello all,
I am new to watercolor and needing a bit of help on how to work it. I have always loved watercolor, especially combined with ink. I'm having a hard time getting the look that most good watercolor paintings have, that free flowing, running on the page look. Experienced painters always say, "just do what feels RIGHT." But that never works, you have to know the rules in order to break them. SO.
My biggest question is this:"How do you get that "watery" look, yet keep the color you're using very dark. For instance, if I wanted to paint something pure black on my watercolor, but still want the stroke to look watery, how do I do so without diluting the color? I can't seem to find a happy medium. I'll either put too much water and then it turns more gray than black, or not enough in order to keep the color true and the stroke won't look as "flowing" as I would like it to.

I've posted a few links to what I'm talking about. It's not just black I have trouble with, but any color that I need to appear dark. How do I do THIS: