I have used Rapidograph pens for many years. I have just heard about Micron pens, they are apparently disposable and available in very fine points -- as small as 0.2 and 0.25 mm. (For reference, the rapidograph 000 is 0.25 mm)
A pen is only as good as it's pointAn impulse buy (along with a bottle of india ink) was a couple of "nibs" made by a company "Hunt Pens". I bought a 107 (Hawk Quill) and a 102 (Crow Quill), and was sorely tempted by 104 (Finest). Also got a handle to fool with these.
Confidence is key using a pen. Don't think about what you are doing, just dive in and draw the line you want to draw.
I am told that when purchased, nibs have oil or lacquer on them that must be removed before using them. One recommendation is to hold the nib in a candle flame for a few seconds, but I worry about damage (and others do as well). Better yet is to clean with soapy water, or use some organic solvent (denatured alcohol, acetone, xylene, ...). Without this step the oil will repel ink and cause frustration.
It is recommended to always start by dipping the pen in water and then drying it on a towel.
Now I read that the 102 is "Americas most popular art pen", superfine and flexible. The 107 is stiffer than the 102, very durable, for long even lines and cross-hatching. The claim is that the 107 was the Marvel Comics standard lettering pen, whereas the A-5 nib was used to draw balloons, captions and borders.
One artist likes Gillott 303 nibs, they are very fine and flexible, and by no means a beginner nib.
Some people prefer the crow quill to rapidograph or micron pens. They are sharp enough to tear up some paper (the trick is to us appropriate paper and ink).
Recommended papers are Strathmore 300 smooth, Strathmore 500 bristol board (not paper), plate or vellum. (Plate is a smooth surface.) (get pads from bluelinepro.com or dickblick.com)
Hold the pen as close to the tip as possible, and at as shallow an angle as reasonable. Keep the end of the pen low. Surface tension pulls the ink from the pen and onto the paper. Use an inkwell rather than dipping into the bottle and aim for consistency in how deeply you dip the pen (with an inkwell you can dip till the pen touches the bottom and get the same dip each time. Adjust the level to be able to dip just above the opening in the nib and keep adding ink to the well as you work. Use your entire arm, not your wrist.
An interesting trick is to "reset" the nib. Turn it over and press it against some scrap paper until there is a click from the tines crossing. Scary, but some pros do this every 2-3 minutes "whether needed or not".
Rapidograph universal black ink gets high marks. Also Pelikan's Drawing Ink A. Dr. Martin's Black Star is a denser ink (and not the same as the Bombay Black), good for brush work, but not necessarily for pens. India Ink is not generally recommended for pens.
Nibs that begin with "C" are calligraphy nibs.
One person says to start with the 107, as it is easiest to use and lasts longest (but has the least line variation). Then switch to the 102 when you feel confident. Some people move on from there to the 108 (bronze finish flexible quill), but they are tricky and not everyone likes them, they are very flexible, push too hard and get a big blob of ink.
Folks dip the pen into the ink (right up to where the nib becomes a barrel), keep a piece of scrap paper nearby to shake excess ink off onto. Also recommended is a razor blade nearby to scrape crud off the nib, as well as a lighter or candle to burn fibers out of it!
Tom's Pen Info / tom@mmto.org