be prepared to treat your coworkers in the same way you always have
Step-by-step explanation:
a. be prepared to review the keys to being a good manager :
Review is always good and it will not yield any negative consequences.
b. be prepared to learn your new responsibilities :
This definitely needs to be done because you are becoming the boss of what you were doing before and there will be additional responsibilities according the roles. This would yield only positive impact.
c. be prepared to treat your coworkers in the same way you always have
This is one of the risky sentence where the given action might put you in trouble and create negative impression. If you treat your coworkers the same, then the coworkers might not do their work properly or have some negligence which would create negative consequences.
d. be prepared to prove that you are the best fit for the job:
This would yield only positive impact.