Warning: Most automotive oils and fluids are poisonous. In case of contact with skin, wash off immediately, and in case of contact with clothing, change clothes.
Haynes advises. The smell of a leak can tell you what is leaking. Some liquids have a specific color. It's a good idea to wash your car thoroughly and place a clean sheet of paper under it overnight to determine where the leak is. Keep in mind that some leaks can only occur when the engine is running.
Oil may leak from under the drain plug...
... or from under the filter.
Transmission oil may leak from under the cups on the inner ends of the drive shafts.
Leaking antifreeze often leaves crystalline deposits like this.
The leaks on the wheels are most likely brake fluid.
Fluid may leak from the fittings on the rack housing.