I know, I know, prep work sucks but it’s especially important in this project.
Before you start, open any windows you can nearby and use the exhaust fan in your bathroom plus any other plug-in fans you’ve got nearby. Those fumes are no joke.
Clean it really, really well with a household cleaner to make sure all the grime is gone.
It seems kind of counterintuitive but once it’s all clean you’ve got to then run your sander over the whole thing so the paint has something rough to adhere to. Give it all a wipe over with your tack cloth to get rid of any dust.
Next remove any caulk around the edges, corners, wherever there’s caulk or silicone that your paint is going to touch.
To be honest, I skipped this step in the instructions thinking it’d be fine and it did turn out okay, but would’ve been much easier had I have just done what I was told.