A few thoughts that might help.
Ensure you have a staff handbook containing all your policies and procedure notes.
At the settling in session, set out your expectations so the newbie understands the scope of their job and the high standards they need to work to.
I think in a salon environment, problems can arise if a newbie sees other staff members wasting time on their phones, not regularly cleaning up after themselves etc. and mistakenly assume that's the culture of the place. Assuming that your existing staff are conscientious, your new member of staff will want to fit in and so will follow their lead. Consider asking one of your most trusted experienced members of staff to act as an informal mentor for the first 2-3 weeks of settling in to ensure good habits are formed.
Hold regular 1:1 sessions with the newbie to review progress and identify any training needs. Ensure these sessions are supportive and not punitive.