Listen to how she talks about people who left to go to graduate school.
Does your boss speak fondly of former employees who are now in graduate school? Does she mention receiving emails every now and then from them–or has everyone skedaddled without looking back? People usually keep in touch with bosses who were supportive of their graduate school applications. One reason is that at least one class ALWAYS requires that we contact former bosses for feedback.
Contact people who have left working under her management for graduate school.
You have to do this tactfully and respectfully. Find people (via LinkedIn or asking a trusted peer at work) who left from working under your manager to go to graduate school and contact them for a brief chat. During the chat, share your intention of applying to graduate school and ask if your manager was supportive of their applications, as well as ask if they have any tips for how to best approach her, since they’ve already done it successfully (or not so successfully).
Listen to your intuition.
If you feel terrified to ask your boss for a recommendation, it’s probably for a good reason. Though business and policy schools prefer to get a recommendation from your current supervisor, they know that is not always possible. If your intuition is flashing big red lights when it comes to asking your current supervisor for a recommendation, you want to pause and consider alternative sources for a great letter of recommendation.
Pay close attention to your performance evaluations.
The kind of feedback you receive from your boss in performance evaluations is a good indicator of what she will say in your recommendations. If she takes the time to give detailed, specific feedback, she’ll probably take the time to write a thoughtful letter of recommendation. Furthermore, if you’re receiving primarily positive reviews, you should feel great about asking her whereas mixed reviews with lots of places for improvement means you might not have an enthusiastic recommender on your hands.