I found this article by Discovery Channel's How Stuff Works on Dawn's Learnist board:

Good soil is the first step to a great garden. You don't want dead things, do you? Do you want vegetables impregnated with toxic materials? Do you want to fight with your garden to get even the basics to grow?

You can then make the most of the soil in your area by amending it:

So how do you amend soil? The first, most important step is to do a soil test to find out just what your soil is lacking -- and not lacking. Read how to do a soil test.

About Soil teaches the basics about that black, earthy stuff we call soil. You'll learn how to go about getting a soil test and what to do with the results. Whether your soil is nutrient-poor sand, heavy clay, or something in between, this section will offer suggestions on how to alter the nutrients and pH of your soil to make it as fertile as possible. Other important tests discussed in this section are texture and drainage checks that determine how well your soil absorbs and drains water.

Preparing Soil includes how to use inorganic and organic fertilizers as well as other soil-improvement methods, such as composting. You'll learn about the three main nutrients found in most chemical fertilizers -- nitrogen, phosphorous, and potassium, or N, P, K -- and how to read NPK formulas on fertilizer packaging in order to get the right combination for your soil. If you'd rather go the organic route, you'll also find tips on how to make your own compost and about alternative ways to improve your soil conditions without using chemicals.

Soil Techniques address the best ways to prepare your garden bed for planting, such as rototilling and hand digging. Also discussed in this helpful section are the whys and hows of installing a mowing strip around the garden bed to keep grass from growing where your flowers are.You'll also want to turn to this section for tips on special soil techniques, such as double-digging for high-performance beds like rose garden and creating raised beds for very poor soil conditions.

Mulching benefits just about every garden. Not only does it help retain moisture and keep weeds at bay, it often gives a finished look to a yard or garden. This section will help ensure that you lay mulch properly (not too thick!) and that you get the look you'd like to achieve using the various types of mulch available.

The key is to be patient, keep learning, and practice!

I've got to be honest--I never test soil. But I would make an exception for urban areas, especially around here due to lead paint residue and industrial waste. Heavy metals are best left on the playlist. 

That makes sense. But you do amend your soil through mulching, right? Anything else?

Compost, but since this is a new yard, I'm going to go w some fish fertilizer and bone meal. I'm busy sourcing manure--there must be a ton of it around here someone would donate. 

Would cat litterbox activity be a reasonable substitute for manure?

If so, I have four critters who would work overtime for you.

Um, no... but four? Wow. Four real ones or gifs ;)   

Four real cats:

Why do fish fertilizer and bone meal work well?

I miss my kitty. Dog doesn't want another.  Back to fish:  Here, on the coast, it's an easy supply. It's been used by Wampanoags, Narragansetts, and Pequots forever--back to helping the colonists not starve (found this article). Also, it stays with the soil better and has high nitrogen levels. http://urbangardenmagazine.com/2011/02/a-fish-called-fertilizer/

Bone meal is high phosphorus. I add it once in a while when Mother Earth News commands me. This is a huge biochem science, and I'm not testing my soil enough (translate: at all) to be precise here. Imagine someone who probably has ADHD tossing chemicals around a bunch of plants. That's me. Phosphorus helps flowers and also bulbs. I have a notebook of things to throw it at and when. http://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/bone-meal-fertilizer.htm

So it really is about getting the right mix of nutrients into the soil.

Which is why cat droppings might not be as good as manure.

Cat droppings have parasites often... it's why pregnant women don't clean litterboxes. 

Worm poop, on the other hand, is good stuff. (I have a worm farm in my garage.)

Is this why good soil has worms that live in it? Cool, I just learned something!