When selecting an area for your garden soil should be your NO 1 concern. It is possible overtime to create a good soil, but it is far easier to start with one. It is troublesome for me thinking of how to advise one without knowing more information. Naturally your site should have existing plant life. If you are starting with bare ground or limited plant life (ex: striped subdivision lot) you may be starting from scratch. Dense grass whether it be lawn or pasture can be a good start. Healthy woodlands can be good but a lot of work to establish. Fresh water wetlands are rich in organic matter but but must be drained. Review multiple sites by prodding around with a spade shovel take note of organic matter content, soil life and soil texture or take it to the next level and get a soil test/recommendation.
Sunlight; sunlight is our energy source on earth and photosynthesis is how we capture the resource. Putting a garden in the shade or starting plants in a home without proper light levels is foolish. I understand the desire to be fully sustainable by starting your own seeds; but please do it right or don’t do it at all. Your garden should be in direct sunlight.
Microclimate’s can be beneficial. Here in Southern Idaho spring winds can be devastating and protection from the wind can help a great deal. South facing rock walls can build heat during cold and river and streams can moderate temperatures a during high heat or cold.
Proximity to the home, water supply, tool shed, hen house, livestock and more should be considered. Our home garden is set close to the home where our children play. Often times at our home you can find the kids grazing in the garden on tomatoes, peas, carrots and more; its a site to see.
Now you have selected your site what now? get a proper soil test, balance your soil and build organic matter. Keep reading here is a easy read The Intelligent Gardner by Steve Solomon