I recently purchased a duplex. The duplex has a fenced backyard that is split in half for each side. However on the side of the house there is more land than I originally realized. I have been doing a lot of yard work because it was overgrown with weed. My question is what can I do with the land? at the very least I can extend the fence for a large back yard. I was wondering if anyone had any ideas that could create more value in the property.

It really depends on how nice the duplex is and what kind of tenants you want.  A decent option may just be to divide the yard in two if not done so already so that each tenant has their private space and can allow pets to roam a bit more freely.