Step 1: Locate your blueberry patch next to a drainage swale or low spot that will hold seasonal water. The plants will also need supplemental irrigation water to get through the dry times. Hand watering or drip irrigation will work.
Step 2: Ammend and loosen the soil by turning over (Over tilling can actually make clay soil more compact overtime) and adding Peat Moss, Pine Needles, or more severe elemental Sulfur. Just about any Nitrogen compost helps to balance soil pH of 4.5 to 5.5 is the ideal pH for Blueberries.
Step 3: Plant your blueberries add wood mulch around the blueberry plant. The mulch will provide habitat for mycorrhiza and keep the soil moist between waterings.
Step 4: Innoculate your Blueberry plants and mulch with mycorrhiza
Step 5: If plants are not leafing out well or putting on fruit and have plenty of water think about adding an acidic fertilizer in Spring before blossoming and one more dose the last week in Spring. Be sure to continue to keep mulch cover. If you can get more acidic mulchs (oak leaves, pine needles, and pine bark) utilize them.