Where to start? Well, you could start by purchasing just an ordinary black pen with a fibre tip. These are stocked in all stationers, art shops etc, they are very cheap, but they will do the job. This will be fine to do various strokes and is easy to carry on your person. Obviously, how you use your pen makes a difference and what I am meaning here, is how much pressure you put on, or, do not put on the nib. Now you need to choose your subject. Don’t get too ambitious, start small and progress later. Shells, leaves, pebbles, stones are all good, simple choices. You need a bit of detail.Get the facts at Ink Drawing Techniques website
Now you need to create a form and lay a texture. What do we mean by this? You can lay a few dots, lines, dashes, all with more or less pressure giving a rough outline. For example, with your marks close together it will appear darker in intensity. If you want it really dark you can cross hatch. Cross hatching can intensify your work. What actually happens, is you actually draw one set of lines and continue by drawing more lines the opposite way across it, making it much, much darker. Other effective results can be made by giving a feeling of roundness. If you have a crevice on any curve and you make it dark, but then lighter, as you come away from the curve.
Adding a wash to your work makes it more interesting. Many papers will support a pen and wash. Washes adapt well to heavily grained paper, with pens being good on shiny and smooth surfaces. So, now you have done your sketching with your pen, now for paints. Block watercolour paints are ideal diluted with water. Keep your wash thin, otherwise you may block the lines of your drawing. Remember the light will reflect from the white paper. I personally would recommend that you work with a palette which will hold block watercolours, but yet, can be used for mixing your colours too. It saves valuable time if you have your tools as close as possible. It can help to give a mixed look, if your pen runs into your lines, because it was the water soluble type bought.
Washes are not needed to be particularly accurate. When one colour runs into another, it can often add to the effect and become an advantage. Mistakes with pen and ink are a bit of a problem. It does not work to put more layers of paint on, as the paint itself, you could say, is translucent. You can sometimes amend your work with a grainy ink rubber, but do wait until your paint is dry. Do not be heavy handed or it will take away the surface and mess the ink and paint up. So remember, a light touch is needed with the rubber. Leave some white, unpainted, areas on your work to give a bit of contrast!