To care for Calathea lietzei, place it in bright, indirect light and keep the soil consistently moist but not waterlogged, using distilled or filtered water. Ensure it is in a warm environment with high humidity, using a well-draining, peat-based soil mix. Fertilize monthly during the growing season and avoid direct sunlight which can scorch the leaves.  
Light
Provide bright, indirect, or filtered light.
Avoid direct sunlight, which can burn the leaves. 
Watering
Keep the soil consistently moist, but not soggy. 
Check the top inch or two of soil and water when it starts to dry out. 
Use distilled, rainwater, or filtered water to prevent leaf browning from chemicals in tap water. 
Avoid overwatering to prevent root rot. 
Fertilize after watering and Prune only dead leaves as they fully dry out.