The Toyota Camry is a great car. There are some common oil leaks which can be down right annoying. The valve cover gaskets frequently leak (replace spark plug tube seal gaskets and check / adjust valve clearances at the same time. Power steering pump and hoses frequently leak on higher mileage cars. Distributor O-Ring and oil leaking internally in the distributor may be a problem, camshaft oil seals and crankshaft oil seal may cause a leak inside the timing cover.
The most efficient way to pin point the source of the leak is to steam clean the engine add a dye to the oil . With a "clean engine" the dye when viewed under a black light should pin point the source of the leak. Oil leaks may be caused by excessive engine blow bye (engine wear) or a restricted PCV valve. Hope this helps.