How do I (21 F) get my boyfriend (20 M) to listen to me?

We have been together for about 2 and a half years, and it seems like I constantly have to nag him to complete simple requests. For example, for the first three months of us living together (2 years in), he would not put his used cups in the sink. It started with asking nicely and escalated over three months to threatening to break up with him. He. Does. Not. Listen. And over the last few weeks, I keep telling him to spray Potpurri before using the restroom and he never does. Tonight, I was eating and the smell was awful, completely ruining my appetite. Of course, he can't control this, but he can control using the Potpurri like I've asked several times. Everything else is great in our relationship, so there's nothing else to be addressed regarding this situation, but how do I get it through his head that he should actually listen to me?

TLDR: How can I get my boyfriend to genuinely listen and respect when I ask him to do things?