I used a combination of double-dig, close-spacing my plants (I'm sure there's a technical term) and mycorrhizal infused soil (and of
course lots of
compost.
In the middle of a CO drought, my garden (planted about a month later than it should have been) was thriving. Plants were about twice as large and much happier looking than my neighbors. Fungi may not have been the only reason, but I'd guess it played a good part.