I keep my nibs very clean during and after use!
Before writing, I make sure the nib is dry and clean in the flange.
When dipping, I dip far enough for the ink to cover the eyehole in the nib, but not too far where the ink goes into the flange. Takes some getting used to!
While writing, I don’t let the ink dry on my nib. Even if I am pausing for like 8 seconds, I will redip into ink or water just to let it flow again, or clean the whole thing and start again. This makes me write pretty fast!
Once in awhile during the writing, I dip the nib into water and clean it with a paper towel. This keeps the nib super clean so I can produce consistent fine lines (if ink dries on the nib, the lines will get thicker and thicker).
If I accidentally dip the nib too far into ink or water that it goes into the flange, I immediately remove the nib from the holder and wash them both and dry.
If I feel the nib is acting wonky, I dip it in rubbing alcohol or windex to deep clean it. You can also use an ultrasonic cleaner if you have one.
When I am finished, I remove the nib from the holder, wash with water, dry and set it aside. I also make sure the holder is clean and dry.
Long story short: Keep a jar of clean water next to you, and do not let ink or water dry on your nib or holder! The nib is in a constant state of deterioration, either the ink or water will cause it to rust eventually. All this babying will allow your nib to last as long as possible, and your writing will always be at the optimum level with a well taken care of nib.