Study the mechanics inside a stroke.
Pressure, direction, speed and release are easier to understand before they are hidden inside a full alphabet.
The four-point stroke check
Start with entry angle. Then observe how pressure loads, what happens during the turn, and where pressure begins to disappear. A heavy exit and a dark pool can look similar but need different corrections.
The exercise asks you to choose one likely cause, not solve everything at once.
Exercise: three release points
Write the same descending curve in three groups. Release pressure earlier in the first, through the middle of the turn in the second, and slightly later in the third. Label the groups before comparing them.
Exercise: speed without extra pressure
Write the same movement at two slightly different speeds while trying to preserve width. Notice whether slowing down causes unwanted pressure or ink pooling.
Material check
Before diagnosing the hand, make a plain test line. If ink feathers or skips without complex movement, the material combination may be the primary issue.
Practice note
Record nib, paper, approximate slant and the one correction tested. A useful note should let you reproduce conditions later.