Think about what fabric you would find most comfortable, night after night. Breathable fabrics are important, especially if you live in a warm climate or tend to sleep hot. Some stores have sample sheets sets you can feel, so if you can, take advantage of them to find out what fabrics you prefer. Once you know what kind of sheets you want, compare thread counts. A good thread count range is 200 to 800, and remember that a lower thread count can still feel comfortable depending on its finish.