First, it does matter what type of paper you use. Good journal paper, even most mixed media paper (with notable exceptions) is not the same as good water color paper. I had the most irritating experiences with water color in my first art journal. If you use a lot of watercolor on a page, and don't use gesso, which has it's own impact to watercolor, then the paper will begin to disintegrate. Bits of paper will start to appear at the end of your brush not to mention how the paper will began to wilt and buckle. Since, I'm at the end of my first art journal I decided to purchase my next journal with my watercolor work in mind.
Next, there was the matter of the watercolor paint. While there are all kinds of watercolor paint, I have my favorites for both portable and stationary watercolor exercises. For portable watercolor activities, I prefer buying a cheap set of watercolors. There are 36 colors in the Artist's Loft Watercolor Set, which you can purchase for about $5. For stationary activities, I prefer to use a wide range of colors including Winsor & Newton, Prang, and some more exotic choices like Tim Holtz's Distress Stains, Twinkle H2O's (love them).
After that, would be the choice of brushes. I use the water pens for portable watercolor and real watercolor brushes for stationary work.
Finally, for inspiration, I browse through other artist's work, as well as selecting the odd photo from Flicker. Here's a sample of my latest work.
I designed this pattern after watching a youtube video. Each pass of green and olive darkened the coloring. I also saw someone on Youtube doing something similar using a flower stencil and H2O's.
The right watercolor was an interpretation from the Mercedes Cortes watercolor in the Pattern Book.