I'm now applying to graduate school, which means someday l'II rettrrrn to a profession where people need to be nice to me in order to get what they want.
本句的主干是I'm...applying to graduate school.．．o which means someday...get what they want是由which引导的非限制性定语从句，修饰逗号之前的部分；其中where people need to...get what they want是由where引导的限制性定语从句，用来修饰profession；in order to...是该定语从句中的目的状语。apply to的意思是“申请”。如：
If you want to apply to an American university,you should prepare a lot of materials in advance.
to be nice to的意思是“善待”。如：
Alll ever wanted out oflife is to be nice to people and have them be nice to me.
动词不定式在句中可作目的状语，常见的形式为in order (not) to do sth.，意为“为了（不）做某事”，或so as (not) to do sth.，意为“以便（不）做某事”。
in order (not) to do sth.可置于句首或句中。如：
1) In order to make themselves look more beautiful, women o:Ren apply cosmetics to their faces.
2) Women often apply cosmetics to their faces in order to make themselves look more beautiful.
so as (not) to do sth,只能置于句中。如：
Tom kept quiet about the accident so as not to lose his job.