A French drain is a simple but effective way to move standing water, whether it's against a house or in a boggy area of the yard. Water collects in a trench and is diverted through a pipe underground. The lower end of the pipe can be left exposed -- if your yard slopes downward to a short wall next to the driveway, you can extend the pipe through the wall, so that the water drains out. It doesn't have to be exposed. The water can simply settle into the earth, underground, at the end of the drain.
Stake the outline of the French drain. It should run away from buildings and have a slight downward slope.
Dig the trench. If the French drain is moving water away from a house, dig a six-foot-deep trench if the house has a basement. If there is no basement, or if the drain is not intended to move water away from a building, the trench only needs to be two feet deep.
Put a two-inch layer of gravel in the bottom of the trench. Smooth it flat.
Lay perforated pipe the length of the drain. Cover it with one foot of gravel if the trench is two feet deep. Cover it with five feet of gravel if you're installing a drain that's six feet deep.
Cover the gravel with filter fabric. Filter fabric will keep out small bits of organic material that could clog the drain.
Use topsoil to fill the trench to the height of the surrounding area. Let the soil settle for a week, add more soil if needed and then cover with grass.