This is my pen & ink of choice. Sakura micron archival pigma ink comes in a series of nibs or points depending on the thickness of line you desire. Long ago I used a rapidiograph which I had to fill the ink in the cartridge and quite honestly it was a mess.
Begin with a spiral bound journal and make it a goal to sketch once a day. You can search around on line and fine scads of artists and aspiring artists who keep journals and post daily works, be sure and sign and date your work. Soon you will begin to see your own line and style develop.