There are a few different things you can do, in my opinion. For example, you could still use the mirror spell from Spells8 as long as you have a window in your apartment. Just do the spell at the window instead of going outside.
You can also place a mirror in each of your windows with a sigil on the back of it to reflect any baneful magick back to the sender. You can include the stipulation that if the same energy gets bounced multiple times, then it will instead be dispersed rather than sent back to the sender. I hope that makes sense 
It makes sense in my head!
I would also do general wards of your apartment, too. You can create a talisman to leave at your front door, or even get a door decoration that doubles as a protective talisman.
I think layering protections is a great idea, especially if you suspect that someone is targeting you. Adding a Hamsa or Nazaar would be fine!