Soil quality is most important. Most hai soild that I have seen have been heavy clay, difficult to work and not good for veg.
consider mixing your own soil as soil bought from 'garden centres' can be variable quality.
Clay need plenty of humus, rotten manure ( ox, buffalo, pig,) or ground up coconut fibre, from your garden centre, and sand to improve drainage. Sand from local river bed with small stones, <6mm, is ideal, and sieve o remove large stones.
Possibly some lime, (eggshells?) if th soil is acid. Gren veg will need plenty of fertilizer with high nitrogen content.
Plot needs to be in the sun, but with scope to shade the bed to protect newly planted seedlings. Slug killing pellets are essential to protect your plants.
Decide if you want to be totally organic or use chemicals. difficult to avoid pests in a concentrated small bed.