* Under the hood: This box usually contains higher amperage fuses protecting larger electrical components. This is the most likely location for fuses related to things like the engine, headlights, and wipers.
* Inside the car, usually under the dashboard on the driver's side: This box contains lower amperage fuses for interior components like power windows, lights, radio, etc. You might need to remove a small access panel to get to it.
To be absolutely certain, consult your owner's manual. It will have a diagram showing the location of both fuse boxes and a legend identifying which fuse protects which circuit. This is the most reliable way to find the fuse you need.