There are several ways to build a garden; each way is dependant upon your specifics needs, wants, space available, and price range. But once you figure out your garden layout how to make a garden becomes no sweat.

Location:
You should look for place in your backyard that has the highest light to space ratio. It should be place that water is easily accessible, and out of the way of major traffic. Also keep your garden away from the pool, spill-over of the chlorinated pool water will kill your plants. Also check your soil, soil that has a high density will not let water drain. When water does not drain the roots of your plants will rot.

Garden Layout
Your garden layout is important, because it maximizing your growing space. When considering your garden layout: you must understand types of plants, growth space, and growing season. You can go so far proper amounts of sunlight for each plant, and plant according to amount of sun light. However the Garden Layout is very extensive, and I found a link from the University of Illinois that gives a pretty extensive growing and garden layout guide.

http://web.extension.illinois.edu/vegguide/step02.cfm

When you learn how to make a garden, I think it is important to find ways to make your first harvest as plentiful as possible. That is why I recommend using the Raised Garden Bed.
The raised garden bed allows you to create the perfect environment for growing your plants, as well as being an attractive addition to your backyard.

Materials:
The raised bed can be made out of many types of materials: brick, concrete blocks, rock, glass, and lumber. When using lumber make sure your look for untreated wood. The soil, and your plants, can leach the chemicals from the porous wood making your delicious edibles poisonous.

Size:
Most of the D-I-Y articles that I read, suggested using a 3ft x 6ft bed. When I built mine a few years ago, I used the same size. But since then I have built 5ft x 6ft, and a small 4ft x 3ft bed. The height of the bed should be about 2ft.

Construction:
Construction is extremely simple. Begin by clearing your site of any debris, weeds, or any other hazard that will result in creating an uneven surface. Next level your surface with a grader.

I began by emplacing my walls separately. I started with the back, and worked my way to the front. Once each section was complete I affixed them using L-brackets. I sink my entire frame into the soil about six inches. Once my frame is set. I used a loose gravel, so I can have drainage. Once the drainage layer is placed, I can then lay top-soil of my choice. The best part of the raised garden is that you can place any type soil you want; and you can also place soil that fits your garden layout.

Once you have the soil added you can then plant your first round of crops. Remember to leave enough space to work in your garden. Since these boxes can be built as wide as you want them, you can add as many customizations as you would like.