It's worth trying your hand at just using water with the Derwent Watercolor and Inktense Pencils. Use different sized brushes to see how much control you have with the water. Also, try coloring in stages and brush with water, letting it dry, and then going to another color or adjacent color. I usually start with the lightest colors first.
You can dry the work faster with pressing cloths and an iron. Protect your ironing board just in case. You can also use the low setting on a hair dryer.