A good thing to do is remove the plastic motor cover by just pulling up. look at the, front corner bolts.try to twist them. if they move then its you valve cover bolts. its better to replace the gasket and bolts.
to check if its you oil filter housing gasket, look below the oil filter housing. if you have oil build up then most likely its that too. also by looking behind it and will have oil under black manifold.
I have replaced both gaskets my self. its time comsuming but anyone with a tool set can do it.