Answer: Oh my goodness - a clean slate! I think the first thing you should do is take a notebook out into the yard and start dreaming. Decide where you'd like to plant things and write or drawn the measurements out on a piece of paper. You don't have to be precise at this point, just general ideas. Most people take the outside or perimeter measurements and then draw circle, squares or even bubbles where they want to include things. For instance, you already have a veggie garden and you know you'd like to hang-out in the yard and BBQ. So, draw big circles on your paper where you'd like to have room for these things. Identify the other areas; play area, utility area (where trash cans or garden tools will be stored), entertaining area, etc. Once you have a rough idea of what the areas will be designed for, you can get serious about measuring out flower and herb beds, or where you'd like to plant shrubs, etc. Then the fun part comes - visiting the nursery or garden center to see what appeals to you. Make a list of plants you like and then visit the library and check out Sunset Western Garden Book. You can look up each of the plants and decide if the growth habits, etc. will fit your needs.
Then you can invest in a hand trowel, shovel, and rake (for starters), plus some hand pruners and gloves. This will at least provide the basic necessities for keeping your plants in order.
You'll also want to learn about soil types, watering and general lawn and garden maintenance. You'll find a lot of information in Sunset Western Garden Book (you may want to purchase a copy for your very own). And, for more region specific information, you can visit the Arizona Master Gardener website and read their study manual:
Best wishes with your new garden!
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