If a good, strong rain turns your backyard into a swampy mess, the answer is to move the water. And while you could spend your time in your backyard with a bucket, bailing the water like a pirate in a leaky boat, it is simpler to build a drain and let gravity do the work for you. A French drain is simple enough to build that you don't need to be an expert plumber to install it. However, it will take a degree of physical fitness and a willing to invest sweat equity into your yard.
Draw trees and other obstacles onto your topographic map. This will save you labor by avoiding these as you dig.
Sketch out your path for your drain. Your drain should slope away from the spot where water collects so that gravity will take the water away from your location.
Mark your drain path through your yard with spray paint.
Dig a trench over this path that is 12 inches deep and 6 inches wide.
Place a 2-inch layer of gravel at the bottom of this trench.
Insert your pipe into the trench. Turn the holes in the pipe downward so that they face the bottom of the trench and do not fill with debris.
Cover the pipe with gravel by filling the trench to a point 3 inches from the surface.
Add a 2-inch layer of sand over the gravel.
Fill the remaining 1 inch of the trench with topsoil.
Place a layer of sod over the topsoil to hide the presence of the trench.