We elect a senior/experienced team member to provide most on-boarding, and continued assistance/training/mentorship during the new hire's probation period (usually 3 months). We then interview the new hire at the end of their probation period to get feedback on the training they received from the senior member they were paired with, and the on-boarding process in general.

We rotate between the senior members for each new hire, where it makes sense. The senior member in return receives a $ bonus during this time, and their effort also contributes towards their performance review. I've also noticed it helps the new hire integrate with our culture.