Plant a variety of flowers. Many predators and parasites feed on pollen and nectar or use flowers to supplement their food supply if they run low on pests. Plants in the carrot family and mustard family are especially attractive to beneficials. Let a few of the broccoli plants flower. Plan a season of bloom.
Gardeners enjoy having flowers all season as much as the beneficial insects.
Provide water areas with shallow dishes or pebble areas. The larger good guys, toads, will appreciate these areas too. Include some permanent hardscapes such as stone paths and decorative rock.