Looking Like A Gardening Pro

Community Gardens - what started all of this
Container Gardens - First Installment
Pest Control - Second Installment

Third Installment
It's easy to be a beginner and look like a pro with just a few tips. You can read up on other tips if you want, but this will work for the rest of your life if you don't want to go beyond this.

Amending Soil Technical for making it better.

There are strict formulas for good soil. We're not going that deep. All we're going to do is check the soil and add stuff.
It's hard to have too much organic material (floating stuff). So, when in doubt, add organic material.
Testing your soil the easy way:
1 spoon of soil to 5 spoons of water - keep the ratio and it doesn't matter what size your spoon is. Put in glass jar - shake. Let settle for 20 minutes.
Is anything floating? If there isn't much of anything floating - you need to add organic material.
Is there any small pebbles? If not, think about adding a bag or so per year.
Is the water still really cloudy? You have a lot of clay. Add sand, pebbles and organic material.
Organic material is what holds moisture, keeps air in the soil, and feeds the plants and worms. All vital to a good garden!
Pebbles/sand keep the soil from compacting so roots can breathe and water can drain.
You don't need to make it perfect instantly. You can do this throughout the year/years.

Composting - many ways!

Worms - http://www.wormpoop.com/WormBed/WormBed.htm If just one person in your area starts a worm farm, within just a few months, 4 will have enough, and you can keep spreading the wealth! Or, release them (when you have too many) back into the wild to aid the soil that way.
Blender - Using kitchen scraps of everything Except dairy and meat - put in your blender. Just cover with water. Blend until slushy consistency. Pour and mix into the soil around your plants. Instant food for both plant and worm.
Hot Composting - takes more work than the 2 above. A triple bin that the 3 bins are 1 cubic yard each (3'x3'x3') is best. Get enough stuff - a mix of leaves, grass clippings, weeds, kitchen scraps (no dairy or meat!), manure if you can to fill the first bin. Once you have it full, make sure it's as wet as a rung out sponge. Turn it 2-3 times/week. After 2 weeks, turn it into the next bin. Start the first bin over. After 2 weeks of turning both bins a couple times per week, move them over 1 bin. In about 1 week, the third bin is ready to use in the garden. This way gives you a steady supply, which is GOOD if your soil isn't doing so well.
Cold Composting - Easier, but you'll be waiting for a year. Add your organic material - just like above, to a pile - preferably 1 cubic yard, but can be bigger or smaller. Just add without turning - unless you want to stir it up. It's not vital. A year later, move the top layers to a new spot - right by the old pile. Use the old layers in your garden.

Fertilize

What the stupid letters mean:
N - nitrogen - makes pretty leaves
P - phosporous - makes strong roots and stems
K - potassium (potash) - makes pretty flowers and fruits.
I use a generic 10-10-10 or 12-12-12, spread lightly over the garden monthly. Since most of America's un-amended soil is depleted of all nutrients, it won't hurt to use this. Put it down before a nice rainstorm, but not one that you think will go over 1" - as it will wash the fertilizer away.
Letters they don't put in the fertilizer:
Ca - calcium - GREAT roots and fruit that doesn't fall off
It's too pricey so they don't put it in. Grind up eggshells or buy bone meal. Get eggshells at your local breakfast diner. They'll save them for you! I rinse them, bake them at 200 for 10 minutes, then grind them up in blender or mortle and pestle.
Mg - magnesium - Epsom Salts - BIG fruits and blooms. Scatter lightly in garden monthly.
ETOH - alcohol - keeps plants stocky to focus on fruits. 1 ounce per 5 gallons monthly.

Pinching/Planting

Plant seeds at the depth they recommend. Too close and they'll make weak roots. Too deep and they'll never make it to the surface.
Plant plants to the bottom set of the leaves. Will make stronger root system for hot mid-summer days. Place a teaspoon of coffee grounds mixed with ground eggshells in hole with plant. Or water with a liquid fertilizer.
Pinch tops of flowering plants. Stick pinchings in soil - might root and will fill garden in that much more. Pinching will stimulate plant to make more stalks that will hold more blooms.

Mulch

Use 1"-3" of organic material. Leaf mulch is best, but shredded wood will work. I don't recommend anything else. Rocks are too hot, don't hold moisture in and do nothing else for the soil. Bark, virtually the same reason. Pine needles, can be too acidic, blow away, float away and take more nutrients to break down than they release. Ditto pecan shells.
Place all around garden, leaving 1" all the way around the stems of the plants. Helps with bug control.
Mulch will hold moisture, moderate temperature extremes, control weeds and add nutrients to the soil.
AND, will make your garden look VERY polished.