I ordered a few boat cleats from Amazon and made markings on my oar and drilled the holes I needed for screwing in the cleats. If you do not pre-drill holes, you run the risk of splitting your wooden oar.
I screwed in three boat cleats and then attached mounting hooks to the back of the oar. Done. Simple, but really cool according to my son. This would also make an awesome coat rack by an entryway or even a towel rack in your bathroom.