Creative ways to make extra cash off rentals

Hi everybody

I was wondering if anybody has any out of the box ideas for creating a little extra cash flow out of your rentals. For example, the apartment i just leased was a one year deal (only did it because I don't know the area well enought o buy just yet) and they gave us an option to break the lease for an upfront charge of $400.
Any ideas would be appreciated. I know the previous idea probably seems very basic but, i just came out of a back woods town in Alaska and I have a lot of catching up to do as far as learning these creative ways to produce cash flow.

Thanks,
Madison