I use a technique called Square Foot Gardening.
http://www.squarefootgardening.com/My vegetable garden consists of four 8 by 4 foot beds arranged in a rectangle, with paths in between. Each bed is surrounded by cinderblocks. I grow garlic in the cinderblock holes, which are filled with soil. I don't bother with the grids recommended by the website; they are not necessary.
The entire thing is surrounded by bird netting attached to metal posts, to keep out deer. If I didn't do that, the deer would devour everything. The bottom of the netting also has chicken wire to keep out the rabbits.
I dug down 18 inches in each bed and filled it with the Square-Foot mix of 1/3 peat moss, 1/3 coarse vermiculite and 1/3 compost, though I also add a bit of composted manure and lime. I add more every year. The soil is very fluffy and you're not supposed to walk on it. I also built 10-foot-high trellises out of 1-inch metal electrical conduit. I hang cotton clothesline sections from the trellises to train the tomatoes, cucumbers and pole beans up above the ground.
Usually I plant 4 to 6 tomato plants, 5 or 6 cucumbers, 8 pole beans, 4 eggplants, 4 pepper plants, a couple of squash plants, and about 10 bush beans. In early spring I grow cool-season snap peas, spinach and lettuce, but those are finished by the time the other vegetables go in. These provide enough for my family and a little extra for the neighbors. The summer vegetables are interplanted with marigolds, nasturtiums and white icicle radishes to discourage insects.
Last year I set up a rain barrel with a soaker hose running through the 4 beds. To water, all I had to do was flip a small handle on the hose.
My biggest problems are insects and fungal diseases, the latter because of the hot, humid summers in the Washington, DC area. I use Pyola spray (a mix of pyrethrum and canola oil) for flea beetles and cucumber beetles, and bT for squash borers, and am going to try a new organic fungicide treatment this year. Last year I covered the beds with clear heavy plastic to "solarize" them before the planting season. This warms the soil and is supposed to kill some diseases and bugs. It may have helped somewhat.
The blueberry bushes are still young, and last year we picked about 3 quarts. They are in a separate area of the yard.
I hope this information is helpful. We don't have any local trading groups. Most people here commute and work long hours for the federal government or federal contractors, and don't have the time or energy for gardening. And most of my neighbors are elderly retirees with no energy for gardening. I give them my surplus when there's any available.