Fill your pen with ink. Fountain pens use a variety of ink sources. Some use ink cartridges, while others draw ink into an internal sac. To fit a cartridge, unscrew the pen and press the cartridge firmly into the upper section. To fill a pen with an internal sac, place the tip in your ink bottle and depress the plunger or raise the filling lever. Wait while the ink is drawn into the sac.
Write a few sentences to test your pen. You should be using medium or heavy paper with a low pulp count. Thin paper, paper high in pulp or glossy paper may not take fountain pen ink well. If the pen is slow to start, wet the tip of the nib or write a few practice lines on a piece of scrap paper.
Cap your pen whenever you pause your writing. Leaving your pen uncapped can cause the ink in the nib to dry out. Always store your pen with the nib upward.
Clean your pen if it has trouble writing. Run water through the pen until the water flows clear from the nib without any ink in it. Allow the pen to dry before reassembling it.