Speed of performance can be improved through deliberate practice — something that scientists studied decades ago while studying typists:
The key finding is that expert typists have acquired mental representations to allow them to look further ahead in the text while typing in order to prepare for future key strokes in advance (as shown by high speed filming of anticipatory movement of the fingers of typists).
Typists are able to type at their normal speed for years without increasing it. They are, however, also able to increase their speed of typing beyond their normal speed by pushing themselves for as long as they can maintain full concentration, which is typically between 15–30 minutes per day in the beginning of training (Dvorak et al., 1936).
While they push themselves to type at a faster speed — usually around 10–20% faster than their normal speed — typists uncover keystroke combinations that are comparatively slow and poorly executed. This type of practice allows identification and subsequent correction of weaker components that will allow gradual speed-up of performance during an extended series of practice sessions. More generally, deliberate practice in many different domains involves finding methods to push performance beyond its normal comfortable level by maximal concentration — even if that higher level of performance can be maintained only for short time without errors.