Biointensive gardening advocates for intensive planting.
When you position your plants close together, you can grow more food in a smaller area.
Plus, the plants will blanket the soil, decreasing weed growth, erosion, and soil evaporation.
(My article on intensive planting vs. other methods is here)
Grow biointensive uses the triangle method of placing plants, which allows you to fit 15% more plants into your area than if you planted in squares, while still giving the same distance between plants.
To do this, you can find or make triangle templates (or hexagon templates, which are just 6 equilateral triangles when you think about it) of various sizes to use to layout various plant spacings.
It’s much more efficient than square foot gardening, but also more complicated. Personally, I do often plant in triangles, but I generally eyeball it rather than using templates.
While planting this densely does decrease evaporation from the soil, it still needs more water per square foot than a further-spaced-apart garden.
If I were gardening without access to much water, I would try out Steve Solomon’s methods of very wide plant spacing, giving each of their root systems access to more soil, therefore more water.
Speaking of which, here’s an article I wrote comparing intensive planting methods to other methods of gardening.