Once all of the dead grass has been removed, you need to start loosening the soil. This will make it easier for seeds to take root. It is recommended that you loosen around 2 to 3 inches of top soil with a spade before you move on.
If your grass was killed by poor soil conditions, this is when you will need to treat this issue. As you loosen the soil, you will be able to incorporate some compost or other organic matter. Of course, you should test your soil before you do this because you do not want to upset the pH balance.
If your soil is too acidic for grass to grow, you will need to add an alkaline product. The opposite will need to occur if your soil is too alkaline. After adding the compost or organic material to the soil, you will need to retest it to ensure that you have a balanced pH level.