Assuming you're in the Phoenix or low-desert area given your post...

One of the first things you're going to want to decide is if you want to grow in your native soil and work around/with it...or amend your soil (recommended for broader crop choices).

If you want to amend your soil you're going to want to find a good supply of top soil and/or compost and dig/till some of that into your native soil and/or use a raised bed which will eventually (though weathering, watering, roots, worm, etc. activity move that "good" soil deeper into your native soil). Even if you don't want to dig/till and just top-apply...you might want to stick a shovel into your planting area to check for hard pans of rocks or caliche deposits that would impede root growth.

Myself, I would highly suggest a raised bed or semi-dug-raised bed as a starting point...at least enough to give the crops a good first 6-12" of quality soil. I would also suggest starting a compost pile if you have the room in order to give your beds a consistent source of organic matter (which will degrade much faster in this climate once applied to beds).

Once you've picked out a space and you know what kind of soil amendment you're going to use (if any at all) then you need to get your plant choice and rotation down. While you can grow year-round in the climate, there's some stuff you won't be able to keep productive during the "hell of summer." There are plants that don't mind the intense summers and will provide you with harvestable food...okra, black eye peas, yard long beans, some corn, melons, armenian cukes, and squash. There's other stuff that will produce during the summer, but benefit from shade cloth...smaller tomatoes, some eggplant, peppers, etc...

Planting time is important. While you may get lush greenery growing if you plant late, you don't want them to get to a point where it's too hot or too cold to properly fruit after flowering...the window on some stuff (especially pre-summer) can be quite picky.

There's a few good planting calendars for the area...especially the "Low Desert Planting & Harvest Calendar" or the "Vegetable Planting Calendar for Maricopa County" which can be found via a web search.

A proper watering schedule and pest control issues are also important, but others can give you better advice that I can on that.

Oh yeah, a few other things...

...mulch for water retention and soil cooling...straw is especially good, 2-3 inches of it at least during the warmer parts of the year.

...if/when you start to grow a good amount of food, look into preservation methods. Pickling, freezing, canning, etc... http://nchfp.uga.edu/ is a good starting point for this.

...organic fertilizers...compost provides a small amount. There's a lot of options in the organic fertilizer realm, but some are more expensive than others. Blood meal provides good bang for the buck when it comes to N. Bone meal also provides good bang for the buck when it comes to P (and a little bit of N), but unlike blood meal it is quite slowly available to plants. Some plants are heavier feeder than others...corn needs a lot of N...most peas/beans do not. You're going to want to research what organic nutrient amendments you want to use in your garden and what makes the most sense for what you're trying to grow.

...if you choose not to amend your soil and grow in your native soil you will probably want to add something to your soil to lower your pH into a better range for crops or pick high pH tolerant crops to plant. You'll also probably want to investigate locally grown/native crops to the area which are naturally more tolerant to the soil types if you choose not to amend your soil. Native Seeds/SEARCH specialize in these types of seeds in this area.

Wow this is such good information. Thanks for the detailed explanation. I'm going to try your tips out for the fall! I feel it's my destiny to get this garden working this time. Wish me luck! I'll take pictures and post them to let you know how it turns out this year.

Here is a link that might be useful: Classic Sugar Boutique

Remember that we have a flipped gardening season.

What we grow in out winter is what most people grow in spring and summer. Lettuce, oriental greens, spinach, chard ... all winter. :)

Some of the easiest things to grow in nsummer here are okra and Armenian cucumbers (snake gourd). Basil is also easy.

You will need a reliable watering system. For your first tomato, eggplant, and chili efforts, start with seedlings from a nursery, and buy them as soon as you see them. Herbs too. Get used to keeping things alive before you try growing from seed. It's not as easy as people make it sound.

Roma tomatoes, serrano chilis, and Black Beauty eggplants are reliable producers here. Heirloom stuff ... not so much unless you can find something that's a local heirloom, selected for the heat.

Summer squash grows well here, and it's fast from seed as soon as it's warm.