1. Use fresh or frozen blueberries and do not thaw frozen berries 2. do not overmix after adding flour to prevent a tough loaf 3. toss berries with flour to reduce sinking and bleeding 4. swap sour cream for Greek yogurt 5. add lemon zest or a pinch of cinnamon for flavor 6. store wrapped at room temperature 2 days or refrigerate up to 5 days or freeze slices up to 2 months