Answer: Azaleas have special requirements. You should first make sure that the plants you purchase are considered winter hardy in your area.
They must have soil that is organic and humusy, evenly moist yet well drained (never sopping wet or saturated, never dried out) and acidic.
They do well in sun all morning or in bright dappled light all day. Protection from winter wind is helpful.
They are sensitive to being planted too deeply, so take care at planting that they sit no deeper or even a half inch higher than they grew in the nursery container.
After planting, mulch with two inches of pine bark mulch to help keep the soil evenly moist and feed the soil slowly as it breaks down.
Water as needed to keep the soil damp like a wrung out sponge, use your finger to dig into the soil and see if you need to water. If it is still damp, do not water yet.
You can fertilize each spring with a slow release granular fertilizer for acid loving plants such as Hollytone. Read and follow the directions. Generally they are easy to care for as long as the soil and lighting are suitable.
If you have had consistent problems, you might want to consult with your county extension. They can help you run basic soil tests and recommend any changes needed there. They can also help you troubleshoot what has happened in the past.
I hope this helps!
Q&A Library Searching Tips