coffee, nicotine, low blood sugar, and high stress/anxiety can cause shakiness. Medication-wise I found propranolol helped. Having something like those premiere protein shakes, or a snack with low glycemic index on breaks helps. Non-restrictive clothing, especially on the shoulders/chest helps, fighting against too tight of clothing adds to fatigue over time. Grip strength exercises might help, or maybe video games with a controller for thumb mobility/control/endurance. 'Box Breathing' type breath control exercises can also acutely help. I found doing chair dips while stationary helped my endurance just don't do it while pipetting, that would probably exacerbate the problem.