Hi there! I would say the biggest thing would be to make sure to move your crops around. Make sure not to put similar plants in last years location, so any disease lingering in the soil will not have its regular target to attack next year. You don't have to move the planting location drastically apart - just shift the location ten feet or so, more if your feeling paranoid.
You might want to also take a look at planting specific disease resistant varieties of particular plants in the garden next year, if disease was a severe issue this year.