You need to consider
the physical properties:
Durability- strength and resistance.
Thermal conductivity- warmth.
Comfort- stretch and absorbence.
Washability- machine, dry time and shrinkage.
Flammability- fire resistance.
and the asthetic properties:
Drape- how it hangs or falls.
Lustre- reflection of light.
you also need to consider these issues;
Cultural- religion and culture.
Ethical- work conditions and wage.
Sustainability- effects on environment.