Practice with the reagents you will be using before starting a prep.
Several factors such as humidity, room temperature and the specific nozzle can have large effects on dispensing accuracy.
As an example, for dispensing mTRAQ labels, I use DMSO as I found it easiest to work with, however, we have also used Ethanol and IPA for dispensing mTRAQ in the past. This can work well, but, requires you to aspirate air and then ~20 uL of organic solvent prior to aspirating label and dispensing.
Some tips that have worked for me:
1) the trypsin is highly viscous, so be sure to run "dip wash" after aspirating, and reduce frequency, voltage, and pulse considerably
2) if a droplet seems to be shooting off to the side, dabbing the bottom of the tip twice with a kimwipe (damp with ethanol) can really help. If the issue persists, move nozzle to home position, turn on continuous dispensing, and try cleaning tip with an ethanol-dampened kimwipe for ~60 seconds.
3) Generally higher voltage has helped with DMSO dispensing. Also make sure humidity is not too high when dispensing DMSO, this can cause droplets to stick to the end of nozzle.