Water color paint, fabric dyes and dye paints have very similar qualities. All three of these mediums are applied primarily as liquids and are relatively translucent and stain the surface. Oil and Acrylic paints, in comparison, are more viscous and opaque allowing them to lay on top of one another and the surface.
With Oil and acrylic paints you can easily work from back to front. This means that the darkest values can be placed on the surface first, then the medium values can be added with highlights as the final touches. Pre-planning of color placement can be more spontaneous and errors are more readily corrected. If you want to paint something white, you use white paint.
Watercolor painting and painting with dye or dye paint, on the other hand, requires that you work from front to back planning the placement of highlights and the lighter values before you even touch the surface. These areas must be preserved by masking or working carefully around them. If you want to have something be white, you must leave the white of the surface showing. Once the pigment hits the surface, it is there for good. Errors must be masked by altering the design or forgiven.
To maintain a Hard Line of color with watercolor and dye/dye paint, great care must be taken to make sure you are not working into, or next to a wet area. The loading and preparation of your brush before touching the surface is also vital in order to prevent bleeding where you don’t want it.
I find that because of the many similarities between watercolor painting and using dyes and dye paints on fabric, a familiarity of basic watercolor techniques helps a textile artist make an easy transition into controlled dyeing.
Here is a link to some free tutorials to get you started.